Flow meter

ABSTRACT

An flow meter includes a coupler, a support member, an image sensor, and one or more processors. The coupler is adapted to couple to a drip chamber. The support member is operatively coupled to the coupler. The image sensor has a field of view and is operatively coupled to the support member. The image sensor is positioned to view the drip chamber within its field of view. The one or more processors are operatively coupled to the image sensor to receive data therefrom. The one or more processors (1) receive image data from the image sensor, and (2) determine an existence of a free flow condition by identifying an optical distortion of an area behind the free flow condition within the drip chamber using the received image data.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation Application of U.S. patentapplication Ser. No. 14/213,373, filed Mar. 14, 2014 and entitledSystem, Method, and Apparatus for Monitoring, Regulating, or ControllingFluid Flow which is a Continuation-In-Part of U.S. patent applicationSer. No. 13/834,030, filed Mar. 15, 2013 and entitled System, Method,and Apparatus for Monitoring, Regulating, or Controlling Fluid Flow, nowU.S. Publication No. US-2013-0310990-A1, published Nov. 21, 2013, whichis a Continuation-In-Part application of U.S. patent application Ser.No. 13/723,244, filed Dec. 21, 2012 and entitled System, Method, andApparatus for Monitoring, Regulating, or Controlling Fluid Flow, nowU.S. Publication No. US-2013-0188040-A1, published Jul. 25, 2013, whichclaims priority to and the benefit of the following:

-   U.S. Provisional Patent Application Ser. No. 61/578,649, filed Dec.    21, 2011 and entitled System, Method, and Apparatus for Infusing    Fluid; and-   U.S. Provisional Patent Application Ser. No. 61/679,117, filed Aug.    3, 2012 and entitled System, Method, and Apparatus for Monitoring,    Regulating, or Controlling Fluid Flow, each of which is hereby    incorporated herein by reference in its entirety.-   U.S. patent application Ser. No. 14/213,373, filed Mar. 14, 2014 and    entitled System, Method, and Apparatus for Monitoring, Regulating,    or Controlling Fluid Flow also claims the benefit of U.S.    Provisional Patent Application Ser. No. 61/900,431, filed Nov. 6,    2013 and entitled System, Method, and Apparatus for Monitoring,    Regulating, or Controlling Fluid Flow, which is hereby incorporated    herein by reference in its entirety.-   U.S. patent application Ser. No. 13/834,030, filed Mar. 15, 2013 and    entitled System, Method, and Apparatus for Monitoring, Regulating,    or Controlling Fluid Flow, now U.S. Publication No.    US-2013-0310990-A1, published Nov. 21, 2013, is a    Continuation-In-Part application of PCT Application Serial No.    PCT/US12/71142, filed Dec. 21, 2012 and entitled System, Method, and    Apparatus for Monitoring, Regulating, or Controlling Fluid Flow, now    WO Publication No. WO-2013-096722, published Jun. 27, 2013, which    claims priority to and the benefit of the following:-   U.S. Provisional Patent Application Ser. No. 61/578,649, filed Dec.    21, 2011 and entitled System, Method, and Apparatus for Infusing    Fluid; and-   U.S. Provisional Patent Application Ser. No. 61/679,117, filed Aug.    3, 2012 and entitled System, Method, and Apparatus for Monitoring,    Regulating, or Controlling Fluid Flow, each of which is hereby    incorporated herein by reference in its entirety.

The present application is also a Non-Provisional application whichclaims the benefit of U.S. Provisional Patent Application Ser. No.61/900,431, filed Nov. 6, 2013 and entitled System, Method, andApparatus for Monitoring, Regulating, or Controlling Fluid Flow, whichis hereby incorporated herein by reference in its entirety.

BACKGROUND

Relevant Field

The present disclosure relates to a flow meter. More particularly, thepresent disclosure relates to a flow meter that may monitor, regulate,or control fluid flow, for example, for use in medical applications suchas intravenous infusion therapy, dialysis, transfusion therapy,peritoneal infusion therapy, bolus delivery, enteral nutrition therapy,parenteral nutrition therapy, hemoperfusion therapy, fluid resuscitationtherapy, or insulin delivery, among others.

Description of Related Art

In many medical settings, one common mode of medical treatment involvesdelivering fluids into a patient, such as a human, animal, or pet. Theneed may arise to rapidly infuse fluid into the patient, accuratelyinfuse the fluid into the patient, and/or slowly infuse the fluid intothe patient. Saline and lactated ringers are examples of commonly usedfluids. Such fluids may be used to maintain or elevate blood pressureand promote adequate perfusion. In the shock-trauma setting or in septicshock, fluid resuscitation is often a first-line therapy to maintain orimprove blood pressure.

Delivery of fluid into the patient may be facilitated by use of agravity-fed line (or tube) inserted into the patient. Typically, a fluidreservoir (e.g., an IV bag) is hung on a pole and is connected to thefluid tube. The fluid tube is sometimes coupled to a drip chamber fortrapping air and estimating fluid flow. Below the fluid tube may be amanually actuated valve used to adjust the flow of fluid. For example,by counting the number of drops formed in the drip chamber within acertain amount of time, a caregiver can calculate the rate of fluid thatflows through the drip chamber and adjust the valve (if needed) toachieve a desired flow rate.

Certain treatments require that the fluid delivery system strictlyadhere to the flow rate set by the caregiver. Typically, suchapplications use an infusion pump, but such pumps may not be used in allsituations or environments.

SUMMARY

Briefly, and in general terms, the present disclosure relates to asystem, method, and apparatus for monitoring, regulating, or controllingfluid flow, for example, for use in medical applications such asintravenous infusion therapy, dialysis, transfusion therapy, peritonealinfusion therapy, bolus delivery, enteral nutrition therapy, parenteralnutrition therapy, hemoperfusion therapy, fluid resuscitation therapy,or insulin delivery, among others. More particularly, the presentdisclosure relates to a fluid flow meter for monitoring the flow offluids associated with a patient, a valve for regulating the flow offluid associated with the patient, and/or a fluid flow meter coupled toa valve (e.g., arranged in a closed-loop, open-loop, or feedbackconfiguration) to monitor, regulate and/or control the use of fluidassociated with the patient.

In some embodiments of the present disclosure, a flow meter includes oneor more optical sensors to monitor the flow of fluid within a tube, forexample, using an image sensor to monitor drops within a drip chamberattached to the tube. The flow meter may be a stand-alone device, may beused in conjunction with either a pump or a valve, or both, and/or maybe used to provide feedback to any electronic device. The flow meter maybe remotely controlled, e.g., by a monitoring client, a remotecommunicator, a smart phone, a computer, etc. The flow meter may measurethe average flow rate, an instantaneous flow rate, a drop volume, a dropgrowth rate, or other parameter related to fluid flow.

The flow meter may use the flow rate or parameter related to fluid flowto: (1) display the flow rate or parameter on a screen, (2) providefeedback, such as the flow rate or parameter related to fluid flow(wirelessly or via wires), to an infusion pump such as a peristalticpump, (3) provide feedback to a monitoring client or remote monitoringclient such as a smart phone, (4) issue alarms when the flow rate orparameter related to fluid flow is outside a predetermined range, (5)issue an alarm with the flow rate or parameter related to fluid flow isabove a predetermined threshold, (6) issue an alarm when a free flow isdetected, (7) communicate alarms to a pump, a monitoring client, or aremote monitoring client, (8) instruct a valve to stop fluid flow when afree flow is detected, an alarm is issued, and/or the flow rate orparameter related to fluid flow is above a threshold or is outside of apredetermined range, and/or (9) broadcast the flow rate or parameterrelated to fluid flow.

In some embodiments described herein, a valve regulates the flow offluid associated with a patient. The valves disclosed herein may bemanually actuated or may be actuated with an actuator (or both). Thevalve may be used with or without a pump, with or without a flow meter,and/or may be a stand-alone device. The valve may be remotelycontrolled, e.g., by a monitoring client, a remote communicator, a smartphone, a computer, etc. The valve may compress a tube along a portionthat is substantially greater than the diameter of the tube, e.g., 2times greater, 5 times greater, 10 times greater, etc.

The valve may be made of two or more pieces that compress the tube ormay be made of a single piece that compresses the tube as the piece ismoved or deformed. The two or more pieces and/or the single piece may bemade using injection molding, ultrasonic welding, using multiple piecesthat are glued or molded together, or the like. Each of the two or morepieces may be made by one or more subparts that are attachable to eachother either permanently or temporarily. The single piece may be made byone or more subparts that are coupled together either permanently ortemporarily, e.g., using ultrasonic welding, gluing, latching, or othertechnique. The pieces may be plastic, metal, an alloy, a polymer, orother material.

In some embodiments of the present disclosure, a flow meter is coupledto a valve to regulate fluid flow, e.g., fluid flow into a patient. Theflow meter coupled to the valve may be used with a pump, such as aperistaltic infusion pump, or may be used without a pump (e.g., the flowmeter can replace the functionality of a peristaltic pump). The flowmeter and valve combination may be remotely controlled, e.g., by amonitoring client, a remote communicator, a smart phone, a computer,etc. or may be remotely monitored. A monitoring client may control theflow meter or valve, may be a relay between the flow meter and valve,may monitor the operation of the flow meter or valve, may communicateinformation related to the flow meter or valve to a server, and/or maynot be used in the system.

The flow meter may monitor the flow of fluid and make adjustments,directly or indirectly, to a valve or a pump (e.g., an infusion pump).The flow meter may alarm when it detects free flow conditions,determines if the flow rate is greater than a predetermined threshold oris outside a predetermined range, and/or detects any abnormal behavior.The flow meter, in response to an alarm or condition, may cause the flowmeter to stop fluid flow, instruct a valve to stop fluid flow, instructa safety valve to stop fluid flow, notify a monitoring client or remotecommunicator, broadcast the detected condition, or perform a predefineroutine or algorithm.

In certain embodiments of the present disclosure, an apparatus forregulating fluid flow includes a curved, elongated support member and anopposing support member. The curved, elongated support member iselastically deformable and has first and second ends. The opposingsupport member is configured to position a tube against the curved,elongated support member between the first and second ends such thatdeformation of the curved, elongated support member by movement of thefirst and second ends toward each other reduces an internal volume ofthe tube. The opposing support member may be another curved, elongatedsupport member.

The apparatus may include an actuator coupled to the curved, elongatedsupport member to deform the curved, elongated support member bymovement of the first and second ends toward each other by actuation ofthe actuator. In some such embodiments, the actuator may be a leadscrew, and a knob may be coupled to the lead screw to actuate the leadscrew.

The actuator, the curved, elongated support member, and the opposingsupport member may be configured to regulate the fluid flow by actuationof the actuator in accordance with a Gompertz curve. The actuator may befurther configured, in some embodiments, to actuate the first and secondends toward each other along a predetermined portion of the Gompertzcurve. For example, the actuator may only actuate the actuator along aportion of the actuatable range of the curved, elongated support memberand the opposing support member.

The actuator, the curved, elongated support member, and the opposingsupport member may be configured to regulate the fluid flow by actuationof the actuator in accordance with a sigmoid curve. The actuator may befurther configured to actuate the first and second ends toward eachother along a predetermined portion of the sigmoid curve.

The curved, elongated support member may be semi-rigid and/or mayconsist essentially of a stretchable material. The curved, elongatedsupport member may be an arcuate, elongated support member, and/or maybe C-shaped.

The apparatus may further comprise an elongated connecting memberoperatively coupled to the first and second ends of the curved,elongated support member.

In certain embodiments of the present disclosure, the apparatus maycomprise an actuator coupled to the elongated connecting member and thecurved, elongated support member to apply an outward expanding force tothereby deform the first and second ends of the curved, elongatedsupport members toward each other.

In certain embodiments of the present disclosure, the curved, elongatedsupport member is disposed about parallel to the another curved,elongated support member along a substantial portion thereof. Forexample, the curved, elongated support member defines a length, and theanother curved, elongated support member defines a length and the lengthof the another curved, elongated support member is disposedapproximately parallel with the length of the curved, elongated supportmember.

In certain embodiments of the present disclosure, the apparatus includesan actuator operatively coupled to the curved, elongated support memberat the first and second ends, and to the another curved, elongatedsupport member at first and second ends. The actuation of the actuatorcauses the first and second ends of the curved, elongated support memberto approach each other and also causes the first and second ends of theanother curved, elongated support member to approach each other tothereby cause a reduction in distance between the curved, elongatedsupport member and the another curved, elongated support member tothereby compress the tube.

In certain embodiments of the present disclosure, the curved, elongatedsupport member defines a length, and the opposing support member isdisposed orthogonally from the length along a portion thereof.

In certain embodiments of the present disclosure, the curved, elongatedsupport member includes a plurality of ridges disposed thereon to engagethe tube.

In certain embodiments of the present disclosure, the opposing supportmember includes a plurality of ridges disposed thereon configured toengage the tube.

In certain embodiments of the present disclosure, the curved, elongatedsupport member includes a flange extending from a length thereofconfigured to hold the tube. The opposing support member may includeanother flange extending from a length thereof configured to hold thetube such that the flange and the another flange are about parallel toeach other and are about parallel to a central axis defined by the tubewhen the tube is disposed therebetween.

In certain embodiments of the present disclosure, an apparatus forregulating fluid flow includes a first elongated support member, asecond elongated support member, and an actuator. The first elongatedsupport member defines a length, and the second elongated support memberalso defines its own length such that the length of the second elongatedsupport member is disposed in spaced relation with the length of thefirst elongated support member to cooperate with the first elongatedsupport member to compress a tube. The actuator is in mechanicalengagement with at least one of the first and second elongated supportmembers to actuate the first and second elongated support members towardeach other to thereby compress a tube disposed therebetween to regulateflow of fluid within the tube such that actuation of the actuatoractuates the first and second elongated support members to regulatefluid flow within the tube in accordance with an approximate sigmoidcurve.

The length of the second elongated support member may be disposed aboutparallel to the length of the first elongated support member. The firstand second elongated support members may be configured to cooperate witheach other to compress the tube along a length of the tube at leastsubstantially greater than the diameter of the tube. The actuator may beconfigured to actuate the first and second elongated support members tocompress the tube to regulate fluid flow within the tube along apredetermined portion of the sigmoid curve.

In certain embodiments of the present disclosure, an apparatus forregulating fluid flow includes first and second elongated supportmembers. The first elongated support member defines a length and thesecond elongated support member defines a length. The length of thesecond elongated support member is disposed in spaced relation with thelength of the first elongated support member to cooperate with the firstelongated support member to compress a tube. The actuator is inmechanical engagement with at least one of the first and secondelongated support members to actuate the first and second elongatedsupport members toward each other to thereby compress a tube disposedtherebetween to regulate flow of fluid within the tube such thatactuation of the actuator actuates the first and second elongatedsupport members to regulate fluid flow within the tube in accordancewith an approximate Gompertz curve.

The length of the second elongated support member may be disposed aboutparallel to the length of the first elongated support member. The firstand second elongated support members may be configured to cooperate witheach other to compress the tube along a length at least substantiallygreater than the diameter of the tube.

The actuator may be configured to actuate the first and second elongatedsupport members to compress the tube to regulate fluid flow within thetube in accordance with a predetermined portion of the Gompertz curve.

In certain embodiments of the present disclosure, an apparatus forregulating fluid flow includes first and second elongated supportmembers. The first elongated support member defines a length, and thesecond elongated support member defines a length such that the length ofthe second elongated support member is disposed in spaced relation withthe length of the first elongated support member to cooperate with thefirst elongated support member to compress a tube. The actuator is inmechanical engagement with at least one of the first and secondelongated support members to actuate the first and second elongatedsupport members toward each other to thereby compress a tube disposedtherebetween to regulate flow of fluid within the tube such thatactuation of the actuator actuates the first and second elongatedsupport members to regulate fluid flow within the tube in accordancewith an approximate generalized logistic function.

The length of the second elongated support member may be disposed aboutparallel to the length of the first elongated support member. The firstand second elongated support members may be configured to cooperate witheach other to compress the tube along a length of the tube at leastsubstantially greater than the diameter of the tube. The actuator may befurther configured to actuate the first and second elongated supportmembers to compress the tube to regulate fluid flow within the tube inaccordance with a predetermined portion of the generalized logisticfunction.

In certain embodiments of the present disclosure, an apparatus forregulating fluid flow includes first and second support members, and anactuator. The first support member forms at least one of an arc, aplurality of arcs, a curve, a plurality of curves, an arcuate shape, aplurality of arcuate shapes, an S-shape, a C-shape, a convex shape, aplurality of convex shapes, a concave shape, and a plurality of concaveshapes. The second support member is disposed in spaced relation withthe first support member to cooperate with the first support member tocompress a tube along a length of the tube at least substantiallygreater than the diameter of the tube. The actuator is in mechanicalengagement with at least one of the first and second support members toactuate the first and second support members toward each other tothereby compress a tube disposed therebetween to regulate flow of fluidwithin the tube such that actuation of the actuator actuates the firstand second support members to regulate fluid flow within the tube inaccordance with an approximate nonlinear function.

The approximate nonlinear function may be an approximate generalizedlogistic function, an approximate sigmoid curve, and/or an approximateGompertz curve. The actuator may be configured to actuate to therebyregulate the fluid flow within the tube in accordance with apredetermined portion of the approximate nonlinear function.

In certain embodiments of the present disclosure, the first supportmember forms an arc, has a shape consisting essentially of an arc, formsa plurality of arcs, has a shape consisting essentially of a pluralityof arcs, forms a curve, has a shape consisting essentially of a curve,forms a plurality of curves, has a shape consisting essentially of aplurality of curves, forms an arcuate shape, has a shape consistingessentially of an arcuate shape, forms a plurality of arcuate shapes,has a shape consisting essentially of a plurality of arcuate shapes,forms an S-shape, has a shape consisting essentially of an S-shape,forms a C-shape, has a shape consisting essentially of a C-shape, formsa convex shape, has a shape consisting essentially of a convex shape,forms a plurality of convex shapes, has a shape consisting essentiallyof a plurality of convex shapes, forms a concave shape, has a shapeconsisting essentially of a concave shape, forms a plurality of concaveshapes, and/or has a shape consisting essentially of a plurality ofconcave shapes.

A length of the second support member may be disposed about parallel toa length of the first support member. The first and second supportmembers may be configured to cooperate with each other to compress thetube along a length of the tube at least substantially greater than thediameter of the tube.

In certain embodiments of the present disclosure, an apparatus forregulating fluid flow includes a curved, elongated support member and anopposing support member. The curved, elongated support member iselastically deformable and has first and second ends. The opposingsupport member is configured to define a conduit with the curved,elongated support member such that the conduit is defined between thecurved, elongated support member and the opposing member; Deformation ofthe curved, elongated support member by movement of the first and secondends toward each other reduces an internal volume of the conduit. Insome embodiments, the conduit may be configured to receive a tube. Inyet additional embodiments, the conduit is fluidly sealed, and theapparatus further comprises first and second ports in fluidcommunication with the conduit such that each port is adapted for beingcoupled to a tube.

In certain embodiments of the present disclosure, a system forregulating fluid flow includes a flexible tube and aninverse-Bourdon-tube valve. The flexible fluid tube has a fluid path andis configured for passing fluid therethrough. The inverse-Bourdon-tubevalve is coupled to the flexible fluid tube to regulate the fluidflowing through the fluid path of the flexible fluid tube. An actuatormay be coupled to the inverse-Bourdon-tube valve to actuate theinverse-Bourdon-tube valve to regulate the fluid flowing through thefluid path of the flexible fluid tube. An inverse-Bourdon-tube valveworks in an opposite way of a Bourdon tube in that a deformation of thefluid path causes changes in fluid flow rather than fluid flow causingdeformation of the fluid path.

In certain embodiments of the present disclosure, a system forregulating fluid flow includes a fluid tube, a valve, and an actuator.The fluid tube defines a fluid path configured for passing fluidtherethrough. The valve is operatively coupled to the fluid tube andincludes first and second flexible members. The second flexible memberis operatively coupled to the first flexible member. The fluid tube isdisposed between the first and second flexible members, and the firstand second flexible members are configured to flex to thereby regulateflow of fluid passing through the fluid tube. The actuator is coupled toat least a first end of the first flexible member and a second end ofthe first flexible member. The actuator may be a lead screw and theremay be an electrically powered motor coupled to the lead screw to turnthe lead screw.

In certain embodiments of the present disclosure, the system may includea knob coupled to the lead screw such that the knob is configured torotate the lead screw. The knob may be engaged by a motor-drivenactuator.

In certain embodiments of the present disclosure, the actuator iscoupled to a first end of the first flexible member and a second end ofthe first flexible member, and the actuator is configured to at leastone of flex the first and second ends toward each other and flex thefirst and second ends away from each other. The actuator may flex thefirst and second ends away from each other and/or the actuator flexesthe first and second flexible members such that the first and secondends approach each other. The first and second flexible members may begenerally rectangular. The first member and/or the second member may betensioned to at least substantially stop fluid flow when the actuatorceases application of a force.

The system may include a flow meter coupled to a drip chamber that iscoupled to the fluid tube such that the flow meter estimates fluid flowthrough the drip chamber and therefore also estimate fluid flow throughthe fluid tube. The flow meter may be an image-sensor-based, flow meter.

The flow meter may be operatively coupled to a motor to actuate thevalve, and the system may include a control component to control themotor to actuate the valve to achieve a desired flow rate as estimatedby the flow meter.

In certain embodiments of the present disclosure, an apparatus forregulating fluid flow includes first and second C-shaped members. Thefirst C-shaped member defines inner and outer surfaces, and the secondC-shaped member defines inner and outer surfaces. At least one of theouter surface of the first C-shaped member and the inner surface of thesecond C-shaped member is configured to receive a tube. The innersurface of the second C-shaped member is disposed in spaced relation tothe outer surface of the first C-shaped member. A substantial area ofthe inner surface of the second C-shaped member may, in some specificembodiments, abut the outer surface of the first C-shaped member.

In certain embodiments of the present disclosure, the second C-shapedmember is flexible and the first C-shaped member is semi-rigid, isrigid, and/or is an elastomer.

A flexible member may be formed from a material selected from the groupconsisting of a plastic, a polymer, a monomer, a polypropylene, athermoplastic polymer, a ceramic, a polyvinyl chloride, and apolyethylene.

In certain embodiments of the present disclosure, an apparatus forregulating fluid flow includes first and second flexible sheets. Thesecond flexible sheet is operatively coupled to the first flexiblesheet. The first and second flexible sheets are configured to receive afluid tube therebetween, and the first and second flexible sheets arealso configured to flex to thereby regulate flow of fluid passingthrough the fluid tube.

The apparatus may include an actuator coupled to a first end of thefirst flexible sheet and a second end of the first flexible sheet. Theactuator may be configured to at least one of flex the first and secondends toward each other and flex the first and second ends away from eachother.

The apparatus may include a lead screw coupled to a first end of thefirst flexible sheet and a second end of the first flexible sheet, and aknob coupled to the lead screw such that rotation of the knob rotatesthe lead screw. The knob may be configured for engagement with amotor-driven actuator whereby the motor-driven actuator actuates theknob.

In certain embodiments of the present disclosure, an apparatus forregulating fluid flow includes first and second curve-shaped members.The first curve-shaped member defines inner and outer surfaces, and thesecond curve-shaped member also defines inner and outer surfaces. Theinner surface of the second curve-shaped member is disposed in spacedrelation to the outer surface of the first curve-shaped member.

At least one of the first and second curve-shaped members may beconfigured to position a fluid tube therebetween. The first curve-shapedmember may be at least one of semi-rigid and rigid. The secondcurve-shaped member may be flexible. The second curve-shaped member maycomprise an elastomer. The first and second curve-shaped members may beflexible.

The apparatus may comprise a connecting member operatively coupled to atleast one of a first end of the first curve-shaped member and a firstend of the second curve-shaped member such that the connecting member isalso operatively coupled to at least one of a second end of the firstcurve-shaped member and a second end of the second curve-shaped member.The connecting member may be flexible, may be rigid, and/or may besemi-rigid.

The apparatus may include an actuator positioned between the connectingmember and the second curve-shaped member to apply a force therebetweenwhen actuated. The actuator may be a lead screw.

In certain embodiments of the present disclosure, an apparatus forregulating fluid flow includes first and second curve-shaped members.The first curve-shaped member defines inner and outer surfaces. Thefirst curve-shaped member has first and second receiving members atopposite ends of the first curve-shaped member. The second curve-shapedmember defines inner and outer surfaces. The second curve-shaped memberhas first and second fasteners at opposite ends of the secondcurve-shaped member. At least one of the first and second fasteners maybe a hook. The first receiving member of the first curve-shaped memberis configured to engage the first fastener of the second curve-shapedmember, and the second receiving member of the first curve-shaped memberis configured to engage the second fastener of the second curve-shapedmember.

At least one of the receiving members may be a cylindrically-shapedmember, such as a barrel nut, configured for coupling to a hook.

At least one of the receiving members may be operatively coupled to anactuator. One or more of the receiving members may be operativelycoupled to an electric motor.

In certain embodiments of the present disclosure, the apparatus furtherincludes an electric motor coupled to the first receiving member suchthat: (1) the electric motor turns a rotor coupled to a shaft havingthreads on an outer surface thereof; (2) the second receiving memberdefines a threaded hole configured to receive the shaft; and (3) thethreaded hole and shaft cooperate together to at least one of increaseor decrease the distance between the first and second receiving memberswhen the electric motor rotates the rotor to thereby rotate the shaft.

In certain embodiments of the present disclosure, an apparatus forregulating fluid flow includes first and second curved, elongatedsupport members. The first curved, elongated support member iselastically deformable and has first and second ends. The second curved,elongated support member is elastically deformable and has first andsecond ends. The second curved, elongated support member is configuredto position a tube against the first curved, elongated support such thatdeformation of the first and second curved, elongated support members bymovement of the first and second ends of the first curved, elongatedsupport member toward each other reduces an internal volume of the tube.

The first connector is coupled to the first end of the first curved,elongated support member and is also coupled to the first end of thesecond curved, elongated support member. The second connector is coupledto the second end of the first curved, elongated support member and isalso coupled to the second end of the second curved, elongated supportmember. The second connector defines a hole. The connecting member hasan end coupled to the first connector and another end configured forinsertion into the hole of the second connector. The connecting memberdefines a threaded rod at least along a portion thereof. The knob has aratchet configured to ratchet onto the connector member when moved fromthe another end of the connecting member toward the end of theconnecting member. The knob is further configured to engage the threadedrod of the connecting member. The knob may include a plurality offingers configured to engage the threaded rod of the connecting member.The knob defines an outer periphery and includes a hole defined at thecenter of the outer periphery of the knob. The hole is configured toreceive the threaded rod. The plurality of fingers each arc to engagethe threaded rod at a respective end of each of the plurality offingers.

The first curved, elongated support member defines a first hole adjacentto the first end of the first curved, elongated support member. The holeis configured to hold a fluid tube.

The first curved, elongated support member may define a first notchadjacent to the first end of the first curved, elongated support membersuch that the notch is configured to receive a fluid tube. The notch mayinclude a neck configured to receive the fluid tube and a circularregion configured to retain the fluid tube.

In certain embodiments of the present disclosure, an apparatus forregulating fluid flow includes a base, a plurality of fingers, and aring. The base defines a hole configured to receive a fluid tube. Theplurality of fingers each has an end coupled to the base. The ring isconfigured to slide from the base and along the plurality of fingers.Movement of the ring away from the base and toward the fingerscompresses the fingers against the tube. The ring is configured tofrictionally lock against the plurality of fingers. Each finger includesan elongated end coupled to the base and a curved end coupled to anopposite end relative to the base.

In certain embodiments of the present disclosure, an apparatus forregulating fluid flow includes a conically-shaped member, acomplementing member, and an actuator. The conically-shaped member has asurface for wrapping a tube therearound. The complementing member isconfigured to engage the conically-shaped member for compressing thetube. The actuator is configured to compress the conically-shaped memberagainst the complementing member to thereby compress the tube.

In certain embodiments of the present disclosure, an intravenousadministration set includes: a flexible tube for directing fluid flowtherewithin; a first port at a first end of the flexible tube; a secondport at a second end of the flexible tube; a curved, elongated supportmember elastically deformable and having first and second ends; and anopposing support member configured to position the flexible tube againstthe curved, elongated support member between the first and second endssuch that deformation of the curved, elongated support member bymovement of the first and second ends toward each other reduces aninternal volume of the tube.

The intravenous administration set may further include a drip chambercoupled to the flexible tube, another port configured to receive asyringe for injection of fluid into the fluid flow within the flexibletube, and/or a slide occluder coupled to the flexible tube configured toengage the flexible tube to occlude fluid flow therewithin.

The first end of the curved, elongated support member may define a firsthole to receive the flexible tube, and the second end of the curved,elongated support member may define a second hole to receive theflexible tube.

In certain embodiments of the present disclosure, a flow meter includesa coupler, a support member, first and second image sensors, and atleast one processor. The coupler is adapted to couple to a drip chamber.The support member is operatively coupled to the coupler. The firstimage sensor has a first field of view and is operatively coupled to thesupport member. The first image sensor is positioned to view the dripchamber within the first field of view. The second image sensor has asecond field of view and is operatively coupled to the support member.The second image sensor is positioned to view the drip chamber withinthe second field of view.

The at least one processor is operatively coupled to the first andsecond image sensors. The at least one processor receives a first imagedata from the first image sensor and a second image data from the secondimage sensor, and the at least one processor estimates at least oneparameter of the liquid within the drip chamber using the first andsecond image data.

The at least one parameter may be one of a type of formation of theliquid, the volume of the liquid, and the shape of the liquid. The atleast one processor may determine an existence of a free flow conditionusing at least one of the first and second sets of image data.

The flow meter may further include a background pattern positionedwithin the field of view of the first image sensor such that the dripchamber is between the first image sensor and the background pattern.

The at least one processor of the flow meter may estimate the at leastone parameter using the first set of image data by analyzing adistortion of the background pattern caused by the liquid within thefirst field of view as viewed by the first image sensor. The backgroundpattern may be an array of lines having at least one angle relative toan opening of the drip chamber when viewed from the first image sensorwithin the first field of view using the first set of image data.

The at least processor may determine a free flow condition exists whenthe liquid causes the array of lines to change angles by distortioncaused by the liquid when in the free flow condition as viewed withinthe first field of view from the first image sensor.

The at least one processor may compare at least one of the first andsecond image data to a background image to estimate the at least oneparameter.

The at least one processor may compare at least one of the first andsecond image data to the background image by calculating at least one ofa difference between the at least one of the first and second image datato the background image, an absolute difference between the at least oneof the first and second image data to the background image, and/or asquared absolute difference between the at least one of the first andsecond image data to the background image.

The flow meter may include a non-transitory, processor-readable memoryin operative communication with the at least one processor such that thememory stores an operative set of processor executable instructionsconfigured for execution by the at least one processor. The operativeset of processor executable instructions, when executed by the at leastone processor, controls the operation of the at least one processor.

In certain embodiments of the present disclosure, a flow meter includesa coupler, a support member, a background pattern, and at least oneprocessor. The coupler is adapted to couple to a drip chamber. Thesupport member is operatively coupled to the coupler. The image sensorhas a field of view and is operatively coupled to the support member.The image sensor is positioned to view the drip chamber within the fieldof view. The background pattern is positioned within the field of viewof the image sensor. The background pattern is positioned such that thedrip chamber is between the background pattern and the image sensor. Theat least one processor is operatively coupled to the image sensor toreceive image data therefrom. The at least one processor is configuredto estimate at least one parameter of liquid within the drip chamberusing distortion of the background pattern caused by the liquid asindicated by the image data. The distortion is viewable within the fieldof view of the image sensor by the image sensor. The at least oneparameter is at least one of a type of formation of the liquid, a volumeof the liquid, and a shape of the liquid. The background pattern may bean array of lines having at least one angle relative to an opening ofthe drip chamber when viewed from the image sensor using the image data.

The at least one processor may determine an existence of a free flowcondition using the distortion of the background pattern caused by theliquid as indicated by the image data. The at least processor maydetermine that a free flow condition exists when the liquid causes thearray of lines to change angles by distortion caused by the liquid whenin the free flow condition as viewed within the field of view of theimage sensor.

The flow meter may further include a non-transitory, processor-readablememory in operative communication with the at least one processor. Thenon-transitory, processor-readable memory may store an operative set ofprocessor executable instructions configured for execution by the atleast one processor such that the operative set of processor executableinstructions, when executed by the at least one processor, controls theoperation of the at least one processor.

In certain embodiments of the present disclosure, a flow meter includesa coupler, a support member, an image sensor, and at least oneprocessor. The coupler is adapted to couple to a drip chamber. Thesupport member is operatively coupled to the coupler. The image sensorhas a field of view and is operatively coupled to the support membersuch that the image sensor is positioned to view the drip chamber withinthe field of view. The at least one processor is operatively coupled tothe image sensor to receive image data therefrom such that the at leastone processor compares an image of the image data to a reference imageto estimate at least one parameter of liquid within the drip chamber.The reference image may be a dynamic reference image. The at least oneprocessor may update the reference image by multiplying each pixel ofthe reference image by a first constant and adding a corresponding pixelof the image multiplied by a second constant.

The flow meter may include a non-transitory, processor-readable memoryin operative communication with the at least one processor. Thenon-transitory, processor-readable memory may include an operative setof processor executable instructions configured for execution by the atleast one processor such that the operative set of processor executableinstructions, when executed by the at least one processor, controls theoperation of the at least one processor.

In certain embodiments of the present disclosure, a method for exposingan image sensor implemented by an operative set of processor executableinstructions configured for execution by at least one processorincludes: selecting a region of interest; determining if a pixel iswithin the region of interest; activating a light of a backlight if thepixel is within the region of interest; and exposing the pixel. Theactivating act may activate a subset of lights including the light ofthe backlight. The light of the backlight may form a uniform backlight.The image sensor may include the region of interest and the pixel.

The operative set of processor executable instructions may be stored ona non-transitory, processor-readable memory in operative communicationwith the at least one processor such that the at least one processor canperform the method.

The at least one processor may be coupled to an image sensor such thatthe at least one processor performs the method using the image sensor.The region of interest may be a region of the image sensor that images adrip chamber. The region of interest may correspond to the drip chamber.

The method may further include: receiving a vertical sync signal fromthe image sensor; and receiving a horizontal sync signal from the imagesensor. The at least one processor may receive the vertical andhorizontal sync signals from the image sensor. The at least oneprocessor may activate the light of the backlight in accordance with atleast one of the vertical and horizontal sync signals. The light may bea light-emitting diode.

In certain embodiments of the present disclosure, a flow meter includesa coupler, a support member, an image sensor, a backlight, and at leastone processor. The coupler is adapted to couple to a drip chamber. Thesupport member operatively couples to the coupler. The image sensor hasa field of view and is operatively coupled to the support member suchthat the image sensor is positioned to view the drip chamber within thefield of view. The backlight has at least one light. The backlight iscoupled to the support member such that the backlight is adapted toilluminate the image sensor to expose the image sensor. The field ofview of the image sensor at least partially images at least a portion ofthe drip chamber. The least one processor is operatively coupled to theimage sensor to receive image data therefrom.

The at least one processor is configured to: select a region of interestof the image sensor; determine if a pixel of the image sensor is withinthe region of interest; activate the light of the backlight if the pixelof the image sensor is within the region of interest; and expose thepixel of the image sensor.

The flow meter may further include a non-transitory, processor-readablememory readable by the at least one processor. The non-transitory,processor-readable memory includes an operative set of processorexecutable instructions stored thereon configured to cause the at leastone processor, when executed, to: select the region of interest of theimage sensor; determine if the pixel of the image sensor is within theregion of interest; activate the light of the backlight if the pixel ofthe image sensor is within the region of interest; and expose the pixelof the image sensor. The at least one processor may be furtherconfigured to: receive a vertical sync signal from the image sensor, andreceive a horizontal sync signal from the image sensor. The at least oneprocessor may activate the light of the backlight in accordance with atleast one of the vertical and horizontal sync signals.

The at least one processor may select the region of interest anddetermine if the pixel of the image sensor is within the region ofinterest in accordance with the image data. The region of interest is aregion of the image sensor that images the drip chamber. The region ofinterest may correspond to the drip chamber.

The at least one processor may activate a subset of lights including thelight of the backlight. The light of the backlight may form a uniformbacklight.

In certain embodiments of the present disclosure, a method includes:capturing an image including an image of a drip chamber using an imagesensor having a field of view including the drip chamber; subtractingthe image from a background image to thereby generate a differenceimage; converting each pixel of the difference image to a true value ifan absolute value of a respective pixel is beyond a predeterminedthreshold or to a false value if the absolute value of the respectivepixel is less than the predetermined threshold; summing each row of theconverted difference image to generate a plurality of summation values,wherein each summation value of the plurality of summation valuescorresponds to a respective row of the converted difference image; andexamining the plurality of summation values. The method may beimplemented by an operative set of processor executable instructionsstored on a non-transitory, processor-readable memory in operativecommunication with at least one processor such that the at least oneprocessor performs the method.

The act of examining the plurality of summation values may includedetermining if a free flow condition exists within the drip chamber.

The act of determining if the free flow condition exists may includedetermining if the plurality of summation values includes a plurality ofcontiguous summation values above another predetermined threshold.

The act of examining the plurality of summation values may includedetermining if a drop has been formed within the drip chamber.

The act of determining if the drop has been formed within the dripchamber may include determining if the plurality of summation valuesincludes a plurality of contiguous summation values within apredetermined range greater than a minimum value and less than a maximumvalue.

The method may optionally include smoothing the plurality of summationvalues prior to the examining act. The smoothing act may be inaccordance with at least one of a spline function, a cubic splinefunction, a B-spline function, a Bezier spline function, a polynomialinterpolation, a moving average, a data smoothing function, and acubic-spline-type function.

The at least one processor may optionally be coupled to the imagesensor, and the at least one processor may perform the method using theimage sensor.

The method may optionally include the act of converting each pixel ofthe difference image to an absolute value of each pixel after thesubtracting act and prior to the converting act.

The method may optionally include the act of converting each pixel ofthe difference image to a squared value of each pixel after thesubtracting act and prior to the converting act.

In certain embodiments of the present disclosure, a flow meter includesa coupler, a support member, a light, and at least one processor. Thecoupler is adapted to couple to a drip chamber. The support member isoperatively coupled to the coupler. The image sensor has a field of viewand is operatively coupled to the support member such that the imagesensor is positioned to view the drip chamber within the field of view.The light is coupled to the support member and is adapted to illuminatethe image sensor to expose the image sensor such that the field of viewof the image sensor at least partially images at least a portion of thedrip chamber.

The at least one processor is operatively coupled to the image sensor toreceive image data therefrom, and the at least one processor isconfigured to: capture an image including an image of a drip chamberusing the image sensor having a field of view including the dripchamber; subtract the image from a background image to thereby generatea difference image; convert each pixel of the difference image to a truevalue if an absolute value of a respective pixel is beyond apredetermined threshold or to a false value if the absolute value of therespective pixel is less than the predetermined threshold; sum each rowof the converted difference image to generate a plurality of summationvalues, wherein each summation value of the plurality of summationvalues corresponds to a respective row of the converted differenceimage; and examine the plurality of summation values.

The flow meter may include a non-transitory, processor-readable memoryreadable by the at least one processor such that the non-transitory,processor-readable memory includes an operative set of processorexecutable instructions stored thereon configured to cause the at leastone processor, when executed, to: capture the image including the imageof a drip chamber using the image sensor having a field of viewincluding the drip chamber; subtract the image from the background imageto thereby generate the difference image; convert each pixel of thedifference image to the true value if the absolute value of therespective pixel is beyond the predetermined threshold or to the falsevalue if the absolute value of the respective pixel is less than thepredetermined threshold; sum each row of the converted difference imageto generate the plurality of summation values, wherein each summationvalue of the plurality of summation values corresponds to the respectiverow of the converted difference image; and examine the plurality ofsummation values.

The at least one processor may be further configured to determine if afree flow condition exists within the drip chamber when the processorexamines the plurality of summation values.

The at least one processor may be further configured to determine if theplurality of summation values includes a plurality of contiguoussummation values above another predetermined threshold when the at leastone processor determines if the free flow condition exists.

The at least one processor may be further configured to determine if adrop has been formed within the drip chamber when the at least oneprocessor examines the plurality of summation values.

The at least one processor may be further configured to determine that adrop has been formed if the plurality of summation values includes aplurality of contiguous summation values within a predetermined rangegreater than a minimum value and less than a maximum value and alocation of the contiguous summation values corresponds to apredetermined range of locations in which a drop can form.

The at least one processor may be further configured to smooth theplurality of summation values prior to when the at least one processorexamines the plurality of summation values.

The at least one processor may smooth in accordance with at least one ofa spline function, a cubic spline function, a B-spline function, aBezier spline function, a polynomial interpolation, a moving average, adata smoothing function, and/or a cubic-spline-type function.

The flow meter may further include a non-transitory, processor-readablememory having an operative set of processor executable instructionsstored thereon. The non-transitory, processor-readable memory is inoperative communication with at least one processor such that theoperative set of processor executable instructions controls theoperation of the at least one processor.

The at least one processor may be further configured to convert eachpixel of the difference image to an absolute value of each pixel afterthe subtraction act and prior to the conversion.

The at least one processor may be further configured to convert eachpixel of the difference image to a squared value of each pixel after thesubtraction act and prior to the conversion.

In certain embodiments of the present disclosure, a method includes:capturing an image of a drip chamber using an image sensor; identifyinga plurality of pixels of interest within the image; determining a subsetof pixels within the plurality of pixels of interest, wherein each pixelof the plurality of pixels is determined to be within the subset ofpixels when there is a path to a baseline corresponding to the dripchamber; performing a rotation operation on the subset of pixels; andestimating a volume of a drop within the drip chamber by counting anumber of pixels within the rotated subset of pixels.

The baseline may be a predetermined set of pixels within the imagesensor. The plurality of pixels of interests may be identified bycomparing the image to a background image.

The method may optionally include one or more of: initializing thebackground image; updating the background image using the image capturedby the image sensor; updating an array of variances using the imagecaptured by the image sensor; and/or updating an array of integers inaccording with the image captured by the image sensor.

The background image may be updated in accordance with:P _(background,i,j) =P_(background,i,j)(1−α_(background))+α_(background) P _(input,i,j).

The array of variances may be updated in accordance with:σ_(temp) ²=(P _(background,i,j) −P _(input,i,j))²σ_(background,i,j) ²=σ_(background,i,j)²(1−β_(background))+β_(background)σ_(temp) ².

Each integer of the array of integers may correspond to a number ofupdates of a pixel of the background image. In some specificembodiments, the comparison of the image to the background image onlycompares pixels within the image to pixels within the background imageif a respective integer of the array of integers indicates a respectivepixel within the background image has been updated at least apredetermined number of times.

The method may optionally include one or more of: identifying a drop inthe image and a predetermined band near an edge of the drop; andinitializing the background image by setting each pixel of thebackground image to the image unless it is within the identified drop orthe predetermined band near the edge of the drop.

The method may further include setting a pixel of the background imageto a predetermined value if a corresponding pixel of the image is withinthe identified drop or the predetermined band near the edge of the drop.The corresponding pixel of the image has a location corresponding to thepixel of the background image.

The method may further include determining a baseline corresponding toan opening of the drip chamber.

The act of determining a subset of pixels within the plurality of pixelsof interest that corresponds to a drop may include determining each ofthe plurality of pixels of interest is within the subset of pixels ifthe respective pixel of the plurality of pixels has a contiguous pathback to the baseline of the drop forming at an opening of the dripchamber.

The method may optionally include one or more of: capturing a firstimage using the image sensor; identifying the drop within the firstimage and a predetermined band near an edge of the drop; initializingthe background image by setting each pixel to the first image unless itis within the identified drop or the predetermined band near the edge ofthe drop; setting pixels within the region of the drop or within thepredetermined band to a predetermined value; initializing an array ofintegers; and initializing an array of variances.

The method may also include one or more of updating the backgroundimage, the array of integers, and/or the array of variances using theimage.

In certain embodiments of the present disclosure, a flow meter includesa coupler, a support member, an image sensor, and at least oneprocessor. The coupler is adapted to couple to a drip chamber. Thesupport member is operatively coupled to the coupler. The image sensorhas a field of view and is operatively coupled to the support member.The image sensor is positioned to view the drip chamber within the fieldof view.

The at least one processor is operatively coupled to the image sensor toreceive image data therefrom, and the at least one processor isconfigured to: capture an image of a drip chamber using the imagesensor; identify a plurality of pixels of interest within the image;determine a subset of pixels within the plurality of pixels of interest,wherein each pixel of the plurality of pixels is determined to be withinthe subset of pixels when there is a path to a baseline corresponding tothe drip chamber; perform a rotation operation on the subset of pixels;and estimate a volume of a drop within the drip chamber by counting anumber of pixels within the rotated subset of pixels.

The flow meter may also include a non-transitory, processor-readablememory having an operative set of processor executable instructionsstored thereon. The non-transitory, processor-readable memory is inoperative communication with the at least one processor such that theoperative set of processor executable instructions controls theoperation of the at least one processor.

The flow meter may also include a non-transitory, processor-readablememory readable by the at least one processor such that thenon-transitory, processor-readable memory includes an operative set ofprocessor executable instructions stored thereon configured to cause theat least one processor, when executed, to: capture an image of a dripchamber using the image sensor; identify a plurality of pixels ofinterest within the image; determine a subset of pixels within theplurality of pixels of interest, wherein each pixel of the plurality ofpixels is determined to be within the subset of pixels when there is apath to a baseline corresponding to the drip chamber; perform a rotationoperation on the subset of pixels; and estimate a volume of a dropwithin the drip chamber by counting a number of pixels within therotated subset of pixels.

The baseline may be a predetermined set of pixels within the imagesensor. The plurality of pixels of interests may be identified bycomparing the image to a background image. The at least one processormay be further configured to initialize the background image and/or toupdate the background image using the image captured by the imagesensor.

The background image may be updated in accordance with:P _(background,i,j) =P_(background,i,j)(1−α_(background))+α_(background) P _(input,i,j).

The at least one processor may be further configured to update an arrayof variances using the image captured by the image sensor.

The array of variances may be updated in accordance with:σ_(temp) ²=(P _(background,i,j) −P _(input,i,j)) ²σ_(background,i,j) ²=σ_(background,i,j)²(1−β_(background))+β_(background)σ_(temp) ².

The at least one processor may be further configured to update an arrayof integers in according with the image captured by the image sensor.Each integer of the array of integers corresponds to a number of updatesof a pixel of the background image.

Optionally, in some embodiments, the comparison of the image to thebackground image only compares pixels within the image to pixels withinthe background image if a respective integer of the array of integersindicates a respective pixel within the background image has beenupdated at least a predetermined number of times.

The at least one processor may be further configured to: identify a dropin the image and a predetermined band near an edge of the drop; andinitialize the background image by setting each pixel of the backgroundimage to the image unless it is within the identified drop or thepredetermined band near the edge of the drop.

The at least one processor may be further configured to set a pixel ofthe background image to a predetermined value if a corresponding pixelof the image is within the identified drop or the predetermined bandnear the edge of the drop.

In certain embodiments of the present disclosure, the correspondingpixel of the image has a location corresponding to a location of thepixel of the background image.

The at least one processor may be further configured to determine abaseline corresponding to an opening of the drip chamber.

The at least one processor may be further configured to determinewhether each of the plurality of pixels of interest is within the subsetof pixels if the respective pixel of the plurality of pixels has acontiguous path back to the baseline of the drop forming at an openingof the drip chamber to determine if the subset of pixels are within theplurality of pixels of interest that corresponds to a drop.

The at least one processor may be further configured to: capture a firstimage using the image sensor; identify the drop within the first imageand a predetermined band near an edge of the drop; initialize thebackground image by setting each pixel to the first image unless it iswithin the identified drop or the predetermined band near the edge ofthe drop; set pixels within the region of the drop or within thepredetermined band to a predetermined value; initialize an array ofintegers; and initialize an array of variances.

The at least one processor may be further configured to update thebackground image, the array of integers, and/or the array of variancesusing the image.

In certain embodiments of the present disclosure, a flow meter includesan image sensor means and a flow rate estimator means. The image sensormeans is for capturing a plurality of images of a drip chamber. The flowrate estimator means is for estimating the flow of fluid through thedrip chamber using the plurality of images.

The flow rate estimator means may include a processor means forestimating the flow of fluid through the drip chamber using theplurality of images.

The flow meter may further include a memory means in operativecommunication with the processor means to provide an operative set ofprocessor executable instruction to cause the processor means toestimate the flow of fluid through the drip chamber using the pluralityof images.

In certain embodiments of the present disclosure, a flow meter includes:a memory means having an operative set of processor executableinstructions configured for being executed; and a processor means forexecuting the operative set of processor executable instructions forimplementing a flow rate estimator means for estimating the flow offluid through the drip chamber using the plurality of images.

In certain embodiments of the present disclosure, a method includes: astep for capturing a plurality of images of a drip chamber; and a stepfor estimating the flow of fluid through the drip chamber using theplurality of images. The method may be implemented by an operative setof processor executable instructions stored on a non-transitory memoryand executed by at least one processor.

In certain embodiments of the present disclosure, an apparatus includes:a coupler adapted to couple to a drip chamber; a support memberoperatively coupled to the coupler; an image sensor having a field ofview and is operatively coupled to the support member, wherein the imagesensor is positioned to view the drip chamber within the field of view;a valve configured to couple to a fluid tube in fluid communication withthe drip chamber, wherein the valve is configured to regulate flowthrough the fluid tube to thereby regulate the fluid flow through thedrip chamber; and at least one processor operatively coupled to theimage sensor to receive image data therefrom, wherein the at least oneprocessor is configured to: capture a plurality of images of the dripchamber using the image sensor; estimate a volume growth rate of a dropwithin the drip chamber using the plurality of images; receive a setpoint corresponding to a fluid flow rate through the fluid tube; adjusta control system in accordance with the estimated volume growth rate ofthe drop to achieve the set point; and output a control signal from thecontrol system to an actuator of the valve to control actuation of thevalve in accordance with the adjusted control system.

The apparatus may include a non-transitory, processor-readable memoryhaving an operative set of processor executable instructions storedthereon. The non-transitory, processor-readable memory may be inoperative communication with at least one processor such that theoperative set of processor executable instructions controls theoperation of the at least one processor.

The apparatus may include a non-transitory, processor-readable memoryreadable by the at least one processor. The non-transitory,processor-readable memory may include an operative set of processorexecutable instructions stored thereon configured to cause the at leastone processor, when executed, to: capture the plurality of images of thedrip chamber using the image sensor; estimate the volume growth rate ofthe drop within the drip chamber using the plurality of images; receivethe set point corresponding to a fluid flow rate through the fluid tube;adjust the control system in accordance with the estimated volume growthrate of the drop to achieve the set point; and output the control signalfrom the control system to an actuator of the valve to control actuationof the valve in accordance with the adjusted control system.

The control system may be at least one of aproportional-integral-derivative control system, a proportional-integralcontrol system, a proportional-derivative control system, a proportionalcontrol system, an integral control system, a neural net control system,a fuzzy logic control system, and/or a bang-bang control system.

The control system may correlate the estimated volume growth rate of thedrop with the fluid flow through the fluid tube.

The valve may include: a curved, elongated support member elasticallydeformable and having first and second ends; and an opposing supportmember configured to position the fluid tube against the curved,elongated support member between the first and second ends, whereindeformation of the curved, elongated support member by movement of thefirst and second ends toward each other reduces an internal volume ofthe fluid tube. The actuator may be configured to move the first andsecond ends toward each other.

The valve may include: a first elongated support member defining alength; and a second elongated support member defining a length, whereinthe length of the second elongated support member is disposed in spacedrelation with the length of the first elongated support member tocooperate with the first elongated support member to compress the fluidtube. The actuator may be in mechanical engagement with at least one ofthe first and second elongated support members to actuate the first andsecond elongated support members toward each other to thereby compressthe fluid tube disposed therebetween to regulate flow of fluid withinthe fluid tube; Actuation of the actuator actuates the first and secondelongated support members to regulate fluid flow within the tube inaccordance with an approximate sigmoid curve.

The valve may include: a first elongated support member defining alength; and a second elongated support member defining a length, whereinthe length of the second elongated support member is disposed in spacedrelation with the length of the first elongated support member tocooperate with the first elongated support member to compress the fluidtube. The actuator is in mechanical engagement with at least one of thefirst and second elongated support members to actuate the first andsecond elongated support members toward each other to thereby compressthe fluid tube disposed therebetween to regulate flow of fluid withinthe tube; Actuation of the actuator actuates the first and secondelongated support members to regulate fluid flow within the fluid tubein accordance with an approximate Gompertz curve.

The valve may include: a first elongated support member defining alength; and a second elongated support member defining a length, whereinthe length of the second elongated support member is disposed in spacedrelation with the length of the first elongated support member tocooperate with the first elongated support member to compress the fluidtube. The actuator is in mechanical engagement with at least one of thefirst and second elongated support members to actuate the first andsecond elongated support members toward each other to thereby compressthe fluid tube disposed therebetween to regulate flow of fluid withinthe fluid tube; Actuation of the actuator actuates the first and secondelongated support members to regulate fluid flow within the tube inaccordance with an approximate generalized logistic function.

The valve may include: a first support member that forms at least one ofan arc, a plurality of arcs, a curve, a plurality of curves, an arcuateshape, a plurality of arcuate shapes, an S-shape, a C-shape, a convexshape, a plurality of convex shapes, a concave shape, and a plurality ofconcave shapes; and a second support member disposed in spaced relationwith the first support member to cooperate with the first support memberto compress the fluid tube along a length of the fluid tube at leastsubstantially greater than the diameter of the fluid tube. The actuatorin is mechanical engagement with at least one of the first and secondsupport members to actuate the first and second support members towardeach other to thereby compress the fluid tube disposed therebetween toregulate flow of fluid within the fluid tube; Actuation of the actuatoractuates the first and second support members to regulate fluid flowwithin the fluid tube in accordance with an approximate nonlinearfunction.

The valve may include: a curved, elongated support member elasticallydeformable and having first and second ends; and an opposing supportmember configured to define a conduit with the curved, elongated supportmember. The conduit is defined between the curved, elongated supportmember and the opposing member. The fluid tube is disposed within theconduit and deformation of the curved, elongated support member bymovement of the first and second ends toward each other reduces aninternal volume of the fluid tube within the conduit.

The valve may be an inverse-Bourdon-tube valve coupled to the fluid tubeto regulate the fluid flowing through the fluid path of the fluid tube.

The valve may include: a first flexible member; and a second flexiblemember operatively coupled to the first flexible member. The fluid tubemay be disposed between the first and second flexible members. The firstand second flexible members are configured to flex to thereby regulateflow of fluid passing through the fluid tube, and the actuator iscoupled to at least a first end of the first flexible member and asecond end of the first flexible member.

The valve may include a first C-shaped member defining inner and outersurfaces; and a second C-shaped member defining inner and outersurfaces. At least one of the outer surface of the first C-shaped memberand the inner surface of the second C-shaped member is configured toreceive the fluid tube. The inner surface of the second C-shaped memberis disposed in spaced relation to the outer surface of the firstC-shaped member. The actuator is coupled to the first and secondC-shaped members to bend the first and second C-shaped members tocompress the fluid tube.

The valve may include: a first flexible sheet; and a second flexiblesheet operatively coupled to the first flexible sheet. The first andsecond flexible sheets are configured to receive the fluid tubetherebetween. The first and second flexible sheets are configured toflex to thereby regulate flow of fluid passing through the fluid tube.The actuator is coupled to the first and second flexible sheets toregulate flow of fluid passing through the fluid tube.

The valve may include: a first curve-shaped member defining inner andouter surfaces; and a second curve-shaped member defining inner andouter surfaces. The inner surface of the second curve-shaped member isdisposed in spaced relation to the outer surface of the firstcurve-shaped member with the fluid tube disposed between the first andsecond curved-shaped members, and the actuator is coupled to the firstand second curve-shaped members to bend the first and secondcurve-shaped members to thereby regulate the flow of fluid within thefluid tube.

The valve may include: a first curve-shaped member defining inner andouter surfaces, the first curve-shaped member having first and secondreceiving members at opposite ends of the first curve-shaped member; anda second curve-shaped member defining inner and outer surfaces, thesecond curve-shaped member having first and second fasteners at oppositeends of the second curve-shaped member. The first receiving member ofthe first curve-shaped member is configured to engage the first fastenerof the second curve-shaped member. The second receiving member of thefirst curve-shaped member is configured to engage the second fastener ofthe second curve-shaped member. The actuator is coupled to the first andsecond curve-shaped members to bend the first and second curve-shapedmembers to regulate the flow of fluid within the fluid tube disposedtherebetween.

The valve may include: a first curved, elongated support memberelastically deformable and having first and second ends; and a secondcurved, elongated support member elastically deformable and having firstand second ends, wherein the second curved, elongated support member isconfigured to position the fluid tube against the first curved,elongated support member, wherein deformation of the first and secondcurved, elongated support members by movement of the first and secondends of the first curved, elongated support member toward each otherreduces an internal volume of the fluid tube; a first connector coupledto the first end of the first curved, elongated support member andcoupled to the first end of the second curved, elongated support member;a second connector coupled to the second end of the first curved,elongated support member and coupled to the second end of the secondcurved, elongated support member, wherein the second connector defines ahole; a connecting member having an end coupled to the first connectorand another end configured for insertion into the hole of the secondconnector, wherein the connecting member defines a threaded rod at leastalong a portion thereof; and a knob having a ratchet configured toratchet onto the connecting member when moved from the another end ofthe connecting member toward the end of the connecting member, whereinthe knob is further configured to engage the threaded rod of theconnecting member; The actuator may be coupled to the knob to rotate theknob.

The valve may include: a base defining a hole configured to receive thefluid tube; a plurality of fingers each having an end coupled to thebase; and a ring configured to slide from the base and along theplurality of fingers. Movement of the ring from the base compresses thefingers against the fluid tube. The ring is configured to frictionallylock against the plurality of fingers. The actuator is coupled to thering to slide the ring.

The valve may include: a conically-shaped member having a surface forwrapping the fluid tube therearound; and a complementing memberconfigured to engage the conically-shaped member for compressing thetube. The actuator is configured to compress the conically-shaped memberagainst the complementing member to thereby compress the fluid tube.

The control system may be implemented in hardware, software, acombination of hardware and software, and/or by at least one operationalamplifier.

The apparatus may include a non-transitory, processor-readable memory,wherein: the control system is implemented by an operative set ofprocessor executable instructions configured for execution by the atleast one processor, the operative set of processor executableinstructions is stored on the non-transitory, processor-readable memory,and the non-transitory, processor-readable memory is in operativecommunication with the at least one processor to operatively communicatethe operative set of processor executable instructions to the at leastone processor for execution by the at least one processor.

The set point may be compared to the volume growth rate of the drop toadjust the control system. The set point may be compared to the volumegrowth rate of the drop to determine an error signal. The error signalmay be the difference between the set point and the volume growth rateof the drop. The error signal may be passed through a signal processingapparatus to generate the output signal. The signal processing apparatusmay implement a proportional-integral-derivative controller with atleast one non-zero gain parameter.

In another embodiment of the present disclosure, an apparatus forregulating fluid flow includes a curved, elongated support member and anopposing support member. The curved, elongated support member iselastically deformable and has first and second ends. The first end isconfigured to pivotally couple to first and second dog bone linkers, andthe second end is configured to pivotally couple to third and fourth dogbone linkers. The opposing support member is configured to position atube against the curved, elongated support member between the first andsecond ends such that deformation of the curved, elongated supportmember by movement of the first and second ends toward each otherreduces an internal cross-section along a length of the tube. The firstend of the opposing support member is configured to pivotally couple tothe first and second dog bone linkers, and a second end of the opposingsupport member is configured to pivotally couple to the third and fourthdog bone linkers.

The first end of the curved, elongated support member may include anengagement finger configured to engage a rack. The second end of thecurved elongated may be configured to pivotally couple to the rack. Theapparatus may include a knob coupled to the first end of the curved,elongated support member to move the rack.

In yet another embodiment of the present disclosure, a flow meterincludes a coupler, a support member, an image sensor, a laser, and atleast one processor. The coupler is adapted to couple to a drip chamber.The support member is operatively coupled to the coupler. The imagesensor has a field of view and is operatively coupled to the supportmember, and the first image sensor is configured to view the dripchamber within the field of view. The laser is configured to shine theoptical light onto the binary optics assembly.

The at least one processor is operatively coupled to the image sensorsuch that: (1) the at least one processor receives data from the imagesensor having at least a portion of the back pattern representedtherein; and (2) the at least one processor estimates at least oneparameter of liquid within the drip chamber using the image data.

In yet another embodiment of the present disclosure, a flow meterincludes a coupler, a support member, first and second electrodes, andat least one processor. The coupler is adapted to couple to a dripchamber. The support member is operatively coupled to the coupler. Thefirst electrode is configured to couple to a fluid line in fluidcommunication with the drip chamber. The second electrode is configuredto couple to the fluid line in fluid communication with the dripchamber.

The at least one processor is operatively coupled to the first andsecond electrodes to measure a capacitance therebetween, and the atleast one processor is configured to monitor the capacitance. The atleast one processor may be configured to determine if a streamingcondition exists within the drip chamber using the monitoredcapacitance.

In yet another embodiment of the present disclosure, a safety valveincludes a housing, first and second occluding arms, first and secondaxles, and a spring. The housing is configured to hold a tube. The firstand second occluding arms are pivotally coupled together. The first axleis pivotally coupled to a distal end of the first occluding arm. Thesecond axle is pivotally coupled to a distal end of the second occludingarm. The spring is disposed adjacent to the first and second occludingarms on an opposite side to the tube configured to spring load the firstand second occluding arm. The safety valve is configured to dischargethe spring and occlude the tube when the first and second occluding armspivot away from the spring along their common pivot by a predeterminedamount. A solenoid may be used to engage the first and second occludingarms to discharge the spring.

In yet another embodiment of the present disclosure, an apparatusincludes a coupler, a support member, and at least one processor. Thecoupler is adapted to couple to a drip chamber. The support member isoperatively coupled to the coupler. The image sensor has a field of viewand is operatively coupled to the support member. The image sensor isconfigured to view the drip chamber within the field of view. The atleast one processor is operatively coupled to the image sensor toreceive image data therefrom, and the at least one processor isconfigured to: (1) capture an image of the drip chamber; (2) position atemplate within the captured image to a first position; (3) average thepixels within the template to determine a first average; (4) move thetemplate to a second position; (5) average the pixels within thetemplate to determine a second average; (6) determine that the templateis located at an edge of a drop if a difference between the secondaverage and the first average is greater than a predetermined thresholdvalue; (7) and correlate the second position with a volume of the drop.

In yet another embodiment of the present disclosure, a methodimplemented by at least one processor executing an operative set ofprocessor executable instructions configured for being executed by theat least one processor for estimating a flow rate is disclosed. Themethod includes: (1) capturing an image of the drip chamber; (2)positioning a template within the captured image to a first position;(3) averaging the pixels within the template to determine a firstaverage; (4) moving the template to a second position; (5) averaging thepixels within the template to determine a second average; (6)determining that the template is located at an edge of a drop if adifference between the second average and the first average is greaterthan a predetermined threshold value; and (7) correlating the secondposition with a volume of the drop.

In yet another embodiment of the present disclosure, a flow meterincludes a coupler, a support member, a modulatable backlight assembly,an image sensor, and at least one processor. The coupler is adapted tocouple to a drip chamber. The support member is operatively coupled tothe coupler. The modulatable backlight assembly is configured to providea first backlight and a second backlight. The image sensor has a fieldof view and is operatively coupled to the support member. The imagesensor is configured to view the drip chamber within the field of viewand the modulatable backlight assembly. The at least one processor isoperatively coupled to the image sensor and the modulatable backlightassembly such that the at least one processor receives data from theimage sensor having at least a portion of the modulatable backlightassembly represented therein, and the at least one processor isconfigured to modulate the backlight assembly to the first backlightwhen estimating a drop size and to modulate the backlight assembly tothe second backlight. The first backlight may be a diffuser backlighthaving no pattern and the second backlight may be a diffuser backlighthaving a striped pattern.

In yet another embodiment of the present disclosure, a tube restorerincludes first and second gears. The second gear is disposed abuttedagainst the first gear. The first and second gears define a space alongradial portions of the first and second gears to allow a tube to flextherebetween. The first and second gears are further configured torestore the tube when rotated such that the space is not positionedbetween the first and second gears.

In yet another embodiment of the present disclosure, a valve includesfirst and second metallic strips, and first and second guiding members.The first guiding member is coupled to distal ends of the first andsecond metallic strips. The second guiding member is coupled to proximalends of the first and second metallic strips. The first and secondmetallic strips are configured to compress a tube when the distal endsof the first and second metallic strips are actuated towards theproximal ends of the first and second metallic strips. The valve mayfurther include a string (e.g., a metal string or a string made of anyother material) threaded through the first and second metallic strips tospiral around the tube.

In yet another embodiment of the present disclosure, a valve includesfirst and second clamshells configured to provide a cavity between thefirst and second clamshells. The first and second clamshells areconfigure to receive a tube therebetween and within the cavity. Thevalve also includes a bladder disposed within the cavity and a pumpconfigured to inflate or deflate the bladder to regulate flow of fluidwithin the tube.

In yet another embodiment of the present disclosure, an apparatusincludes a coupler, a support member, an image sensor, and at least oneprocessor. The coupler is adapted to couple to a drip chamber. Thesupport member is operatively coupled to the coupler. The image sensorhas a field of view and is operatively coupled to the support member.The image sensor is configured to view the drip chamber within the fieldof view.

The at least one processor is operatively coupled to the image sensor toreceive image data therefrom and is configured to: (1) capture a firstimage; (2) create a first thresholded image from the first image bycomparing each pixel of the first image to a threshold value; (3)determine a set of pixels within the first thresholded image connectedto a predetermined set of pixels within the first thresholded image; (4)filter all remaining pixels of the first thresholded image that are notwithin the set of pixels, the filter operates on a pixel-by-pixel basiswithin the time domain to generate a first filtered image; (5) removepixels determined to not be part of a drop from the first thresholdedimage using the first filtered image to generate a second image; (6)determine a second set of pixels within the second image connected to apredetermined set of pixels within the second image to generate a thirdimage, the third image identifies the second set of pixels within thesecond image; (7) determine a first length of the drop by counting thenumber of rows containing pixels corresponding to the second set ofpixels within the third image, the first length corresponding to a firstestimated drop size; (8) update a background image using the firstimage; (9) create a second thresholded image by comparing the firstimage with the background image; (10) sum the rows of the secondthresholded image to create a plurality of row sums, each row sumcorresponds to a row of the second thresholded image; (11) start at arow position of the second thresholded image having a first sum of theplurality of sums that corresponds to the first length; (12) incrementthe row position until the row position corresponds to a correspondingrow sum that is zero; (13) determine a second length is equal to thepresent row position, the second length corresponding to a secondestimated drop size; and (14) average the first and second lengths todetermine an average length, the average length corresponding to a thirdestimated drop size.

In yet another embodiment of the present disclosure, a methodimplemented by at least one processor executing an operative set ofprocessor executable instructions configured for being executed by theat least one processor for estimating a flow rate includes: (1)capturing a first image; (2) creating a first thresholded image from thefirst image by comparing each pixel of the first image to a thresholdvalue; (3) determining a set of pixels within the first thresholdedimage connected to a predetermined set of pixels within the firstthresholded image; (4) filtering all remaining pixels of the firstthresholded image that are not within the set of pixels, the filteroperates on a pixel-by-pixel basis within the time domain to generate afirst filtered image; (5) removing pixels determined to not be part of adrop from the first thresholded image using the first filtered image togenerate a second image; (6) determining a second set of pixels withinthe second image connected to a predetermined set of pixels within thesecond image to generate a third image, the third image identifies thesecond set of pixels within the second image; (7) determining a firstlength of the drop by counting the number of rows containing pixelscorresponding to the second set of pixels within the third image, thefirst length corresponding to a first estimated drop size; (8) updatinga background image using the first image; (9) creating a secondthresholded image by comparing the first image with the backgroundimage; (10) summing the rows of the second thresholded image to create aplurality of row sums, each row sum corresponds to a row of the secondthresholded image; (11) starting at a row position of the secondthresholded image having a first sum of the plurality of sums thatcorresponds to the first length; (12) incrementing the row positionuntil the row position corresponds to a corresponding row sum that iszero; (13) determining a second length is equal to the present rowposition, the second length corresponding to a second estimated dropsize; and (14) averaging the first and second lengths to determine aaverage length, the average length corresponding to a third estimateddrop size.

In yet another embodiment of the present disclosure, a flow meterincludes a coupler, a support member, first and second loop antennas,and at least one processor. The coupler is adapted to couple to a dripchamber. The support member is operatively coupled to the coupler. Thefirst loop antenna is disposed adjacent to a fluid line in fluidcommunication with the drip chamber. The second loop antenna is disposedadjacent to the fluid line. The at least one processor is operativelycoupled to the first and second loop antennas to measure a magneticcoupling therebetween. The at least one processor is configured tomonitor the magnetic coupling therebetween to determine if a streamingcondition exists within the drip chamber.

In yet another embodiment of the present disclosure, a methodimplemented by an operative set of processor executable instructionsincludes: (1) determining a plurality of points of interest in an image;(2) randomly selecting N-points of interest of the plurality of pointsof interest; and/or (3) identifying a single, unique, geometric featurecharacterized by N-parameters corresponding to N-points of interest.

In yet another embodiment of the present disclosure, a system includes anon-transitory memory and one or more processors. The non-transitorymemory has stored thereon a plurality of instructions. The one or moreprocessors are in operative communication with the non-transitory memoryto execute the plurality of instructions. The plurality of instructionsis configured to cause the processor to: (1) determine a plurality ofpoints of interest in an image; (2) randomly select N-points of interestof the plurality of points of interest; and/or (3) identify a single,unique, geometric feature characterized by N-parameters corresponding toN-points of interest.

In certain embodiments of the present disclosure fluid flow iscontrolled by a valve that deforms a tube using a plunger, a rigidhousing, and substantially incompressible filler. The tube is positionedwithin a channel defined in the filler. A rigid housing creates anenclosure surrounding the filler, the housing has a hole for the plungerto enter the housing and engage the filler. An actuator is connected tothe plunger, controlling the plunger's movement. The force from theplunger engaging the filler is translated to the tube, and causes thetube to deform differing amounts depending on how far the plunger isactuated into the housing.

The filler may have multiple layers of differing stiffness. The softerof the layers can be a material having a shore OO hardness from about 20to about 25. The stiffer of the layers can be a material having a shoreOO hardness of about 15.

The actuator may be a linear actuator that is designed to actuate theplunger into, out of, or both into and out of the housing.

In another embodiment of the present disclosure, the housing may includefirst and second clamshell portions pivotally connected to each other.The portions are connected to allow for “clam like” opening and closing.A latch is connected to the housing to latch the clamshell portions asecured closed position. The first clamshell portion defines a holesized to accept the plunger. A guide connected to the first clamshellportion and the actuator is configured to guide the actuated plungerthrough the hole of the first clamshell portion.

In another embodiment of the present disclosure, the first and secondclamshell portions each define a portion of the cavity created when theportions are in the closed position. The filler located within theclamshell portions has at least two differing hardness layers, and fourlayers total. The first and second layers are within the first portion'scavity, and the third and fourth layers are within the second portion'scavity. The first and fourth layers are disposed on the inner surface oftheir respective clamshell portions. The second and third layers definea channel to guide the tube being valved and are disposed on the firstand fourth layers respectively. The material of the second layer isharder than the material of the first, and the material of the thirdlayer is harder than the material of the fourth.

In yet another embodiment of the present disclosure, a guide isconnected to the first clamshell portion and the actuator to guide theplunger through a hole in the first clamshell portion. At least onespring is connected to the guide and plunger, the spring exerts a forcepulling the plunger towards the housing.

In yet another embodiment of the present disclosure, the actuator isconfigured to be controlled by a monitoring client.

Another embodiment of the present disclosure involves a system tocontrol the flow of fluid through a drip chamber. The system includes adrip chamber coupler, support member, an image sensor, a valve, and atleast one processor. The drip chamber coupler holds the drip chamber,orienting it vertically and in a position capable of being viewed by theimage sensor. The support member is connected to the drip chambercoupler and the image sensor is operatively attached to the supportmember. The images sensor is positioned to have the drip chamber withinits field of view. The valve is fluidly coupled to the drip chamber andhas the ability to control flow through the drip chamber. The valvecomprises a housing, a filler, a plunger, and an actuator. The housingsurrounds a tube that is in fluid communication with the drip chamber,fixed within the housing is the filler. The housing may include firstand second clamshell portions. The first clamshell portion defines ahole and is connected to a guide configured to guide the plunger throughthe hole. The filler has at least two differing stiffness layers to aidin uniform and consistent deformation of the tube. The plunger isconfigured to engage the filler through a hole in the housing andoperatively deform the tube within the filler. The actuator isoperatively connected to the plunger and configured to actuate theplunger. The at least one processor is in communication with the imagesensor and the actuator. The at least one processor is configured toreceive image data from the image sensor, use the image data to estimateat least on parameter of the liquid within the chamber, and then actuatethe plunger to achieve a target parameter. The parameter may beformation of the liquid, volume of the liquid, or shape of the liquid.The target parameter may be a target flow rate or a target drop-growthrate. The processor may determine an existence of a streaming conditionusing the image data.

A background pattern may be positioned within the field of view of theimage sensor, having the drip chamber positioned between the imagesensor and the background pattern.

The housing may include first and second clamshell portions with thefirst portion pivotally connected to the second portion. The portionsare connected in a manner that permits an open position and closedposition that defines a cavity. The first clamshell portion defines afirst portion of the cavity and the second clamshell portion defines asecond portion of the cavity.

The at least two differing hardness layers of the filler may includefirst, second, third, and fourth layers. The first and second layersbeing located within the first portion of the cavity, and the third andfourth layers being located within the second portion of the cavity. Thefirst and second layers are disposed on the inner surfaces of theirrespective clamshell portion, the second layer is disposed on top thefirst layer, and the third layer is disposed on top the fourth layer.The second and third layers are stiffer than the first and secondlayers. A channel is defined in the second and third layers to guide thetube through the filler.

In certain embodiments of the present disclosure, a method includescapturing multiple images of a drip chamber using an image sensor,estimating a flow rate through the drip chamber from the images using aprocessor, receiving a desired flow rate from a user, comparing theestimated flow rate with a desired flow rate using a processor,determining the magnitude and direction of valve actuation to achievethe desired flow rate, and actuating a valve, in accordance with thedetermined magnitude and direction, to achieve the desired flow rate.Actuating the valve may involve adjusting the pressure around a flexibletube having a lumen in fluid communication with the drip chamber todeform the tube and modify the shape of the lumen. The pressureadjustment may be made possible by disposing a rigid housing around thedefined section of the tube, enclosing within the housing asubstantially incompressible filler, and engaging the filler with aplunger thereby increasing the pressure in the housing resulting indeformation of the tube.

The method may also include communicating the estimated flow rate to afluid monitoring client.

The method may also include monitoring for unplanned events and stoppingflow when unplanned events occur.

The method may also include deforming a flexible tube in fluidcommunication with the drip chamber to reduce its lumen size during theprocess of installing or removing the tube from an apparatus performingthis method. Once the process of installing or removing the tube iscomplete, the compressive force is removed from the tube allowing thelumen created by the tube to revert to substantially its initial size.

In certain embodiments of the present disclosure, a system forcontrolling flow through a drip chamber includes a drip chamber holster,an imaging device, a flexible tube, and a valve. The drip chamberholster receives and secures a drip chamber. The imaging device isconfigured to capture images of the drip chamber and create image datafrom the captured images. The flexible tube is connected to the dripchamber and the lumen defined by the tube is in fluid communication withthe drip chamber. The valve is axially disposed around a portion of theflexible tube and controls flow through the tube and ultimately the dripchamber. The valve includes first and second casing components pivotallyconnected to each other and complimentarily align to form an enclosurewhen in a closed position. Inlet and outlet holes are defined in thevalve casing when it is closed and a plunger hole is defined in thefirst casing component. A male latch component is connected to the firsthousing component opposite the pivot connection and a female latchcomponent is coupled to the second housing component opposite the pivotconnection. A substantially incompressible filler is enclosed within thecasing. The filler defines a conduit, sized for a specific tube, whichconnects the inlet and the outlet holes of the valve casing. There are aplurality of variations in the stiffness of the filler. The portion ofthe filler proximate the tube may be stiffer than the surroundingfiller. The plunger is longitudinally aligned with the plunger hole andattached to the actuator. The actuator is configured to actuate theplunger into and out of the plunger hole to engage the filler. Changesin displacement by the plunger alter the forces on the section of thetube within the casing resulting in the lumen changing size. The area ofthe head of the plunger can be smaller than the longitudinalcross-section of the lumen disposed within the housing.

The system may also include a safety cutoff, the safety cutoff comprisesan occluding arms, at least one spring, and a trigger mechanism. Theoccluding arms are configured to compress the tube into a backstop whichreduces the area of the lumen defined by the tube. The at least onespring keeps constant pressure on the occluding arms, forcing themtowards the backstop. The occluding arms are restrained back from thebackstop by a trigger mechanism that can release the occluding arms whentriggered. The trigger mechanism may utilize magnetic force to restrainthe occluding arms, created from adjacently located magnets or from onemagnet within a coil. A first and second magnet may be configured topermit alignment of opposite poles to elicit an attractive magneticforce. A solenoid can be used to apply force to the trigger mechanismcausing it to release the occluding arms. A current responsive materialmay be used to apply force to the solenoid. If first and second magnetsare used, they may be reconfigured to align like poles and apply arepulsive magnetic force to the triggering mechanism. A safety sensorcan be used to sense unplanned events and transmit data of the unplannedevent to a processor that can engage the solenoid and release theoccluding arms.

The system may also include at least one processor, the processor canreceive imaging data from the imaging device, estimate a flow rate basedon the image data, compare the estimated flow rate to a desired flowrate, and adjust the actuator to create the desired flow rate.

The system may also include an enclosure casing, the enclosure casingcomprising a body and a door pivotally connected to the body. When inthe closed position, the door and body create an enclosure that housesthe valve. An arm can be pivotally connected to the door at it firstside and to the female latch component at its second side. The arm isconfigured to unlatch and open the two parts of the valve housing whenthe door is opened, and latch and close the two part of the valvehousing when the door is closed.

The system may also include an arm with a first end pivotally attachedto the door and a second end operatively configured to reset the safetycutoff to a free flow position when the door is opened.

The system may also include a valve having at least one cut off spring,a threaded drive shaft, and a threaded engaging member. The at least onecutoff spring exerts a force on the plunger in the direction of thevalve housing. The threaded driveshaft has a first end attached to theactuator output shaft and an opposite second end connected to theplunger. The connection between the plunger and drive shaft allows theplunger to rotate freely with respect to the drive shaft. The threadedengaging member is operatively connected to the valve casing and isconfigured to engage the threads on the drive shaft. This allows theactuator to control the position of the plunger by rotating the threadeddrive shaft. The engaging member has the ability to disengage from thethreads on the driveshaft leaving only the cutoff spring's to forces theplunger towards the valve housing thereby deforming the tube. A springmay be used to force the engaging member towards the driveshaft. Thesystem may also incorporate an arm with a first end pivotally attachedto the door of the enclosure casing and a second end configured to pushthe threaded engaging member away from the drive shaft when the door isopened.

In another embodiment of the disclosed disclosure an apparatus includesan apparatus casing, a drip chamber, an image sensor, and a valve. Theapparatus casing comprises a body and a door which are pivotallyconnected to each other forming an enclosure when in a closedconfiguration. The drip chamber is connected to the outside of thecasing body. The image sensor is also attached to the outside of thecasing body and oriented so the drip chamber is within its field ofview. The valve is disposed within the apparatus casing and includesfirst and second valve housing components, male and female latchcomponents, a filler, a plunger, and an actuator. The first and secondvalve housing components are pivotally connected to complimentarilyalign and form an enclosure when in a closed position. An inlet hole andan outlet hole are defined when the housing is in a closed position. Thefirst valve housing components has a plunger hole to allow the plungerto enter the casing. The male latch component is attached to the firstvalve housing component and the female latch component is attached tothe second valve housing component, both connected on their respectivehousing components at a location opposite the pivot. The filler is madeof a substantially incompressible material and is enclosed within thevalve casing. A conduit sized for a specific tube is defined within thefiller and connects the inlet and outlet holes of the valve casing. Thefiller is made up of multiple layers of varying stiffness, the layers offiller proximate the conduit can be stiffer than the surrounding layers.The plunger is connected to the actuator and is longitudinally alignedwith the plunger hole. The actuator is configured to urge the plungerthrough the plunger hole. The plunger head can have an area smaller thanthe longitudinal cross-section of the lumen disposed within the housing.

The apparatus may also include a user input device on the door of theapparatus casing, allowing users to manually input information,including desired flow rate, into the apparatus. The apparatus may alsoinclude a display on the door of the apparatus casing configured todisplay infusion information. A touch screen display may be used inconjunction with or in lue of the buttons to allow a user to inputinformation into the apparatus.

The apparatus may also include a processor in communication with theimage sensor and the actuator. The processor receives data from theimage sensor, estimates the flow rate based on the imaging data,compares the estimated flow rate to a desired flow rate, and adjusts theactuator to achieve the desired flow rate.

The apparatus may also include a safety cutoff which includes occludingarms, a backstop, at least one spring, and a trigger mechanism. Thesprings are operatively connected to the occluding arms, urging themtowards the backstop with enough force to compress a tube against thebackstop and reduce the size of the lumen formed within the tube. Thetrigger mechanism releases the occluding arms allowing them to compressthe tube when the mechanism is triggered. A solenoid can be used totrigger the safety cutoff by applying a force to the occluding arms. Asafety sensor may be used in conjunction with a processor to senseunplanned events and engage the solenoid to trigger the occluding armsrelease.

In a certain embodiments of the disclosed disclosure the female latchcomponent is a lever pivotally connected to the valve casing at a pointoffset from its end, this creates a lever having an input end and anopposite output end. The male latch component is a flange. The latchcomponents are position to allow the output end of the female componentto engage the opposing side of the flange when the valve casing is in aclosed position. The lever applies a force to the flange compressing thefirst and second valve casing components together when rotated in thedirection that pushes the output end of the lever into the flange. Aguide arm can be pivotally attached to the door of the apparatus casingat its first end, and to the input end of the female latch lever at itopposite second end. When the door is closed, the guide arm engages theoutput end of the lever with the male latch flange and rotates the leverto compress the valve casing components together.

Certain embodiments of the disclosed disclosure include a compressiontab and a wedge. The compression tab is disposed within an aperture inthe body of the apparatus casing. The tab has a large enough compressiveforce to deform an IV tube positioned between the tab and the body ofthe apparatus casing. The wedge projects out from the door and ispositioned to engage the tab when the door is closed, relieving the tabscompressive forces against the apparatus casing body or the tubetherebetween.

In another embodiment of the disclosed disclosure the valve may includeat least one cut off spring, a threaded drive shaft, and a threadedengaging member. The at least one cutoff spring exerts a force pullingthe plunger and actuator towards the valve housing. The threadeddriveshaft has a first end attached to the actuator output shaft and anopposite second end connected to the plunger. The connection between theplunger and drive shaft allows the plunger to rotate freely with respectto the drive shaft. The threaded engaging member is operativelyconnected to the valve casing and is configured to engage the threads onthe drive shaft. This allows the actuator to control the position of theplunger by rotating the threaded drive shaft. The engaging member hasthe ability to disengaged from the threads on the driveshaft, permittingthe cutoff spring to force the plunger towards the valve casing therebydeforming the tube. A spring may be used to force the engaging membertowards the driveshaft. The system may also incorporate an arm with afirst end pivotally attached to the door of the enclosure casing and asecond end configured to push the threaded engaging member away from thedrive shaft when the door is open.

In another embodiment of the disclosure, an apparatus includes first andsecond metallic structures and an impedance-matching structure coupledwith the first and second metallic structures, with theimpedance-matching structure configured to essentially match a desiredinterrogator frequency. The apparatus also includes a shorting mechanismcoupled with the first and second metallic structures.

The apparatus may include metallic structures that are pre-existingcomponents of an assembly. The apparatus may also include an inductor, acapacitor, or combination of an inductor and a capacitor as theimpedance-matching structure. The shorting mechanism may be a transistoror a switch and may be controlled by a microprocessor.

The apparatus may also include a low pass filter coupled with the firstand second metallic structures and having a cutoff frequencysufficiently below the frequency of a desired interrogator.

In other embodiments of the present disclosure, a method includescoupling a first and a second metallic structure to animpedance-matching structure, with the impedance-matching structureconfigured to essentially match a desired interrogator frequency. Themethod also includes shorting the coupled first and second metallicstructures.

In other embodiments of the present disclosure, the method may furtherinclude coupling a low-pass filter with the first and second metallicstructures. The shorting may be controlled by a microprocessor.

In another embodiment of present disclosure: a system for regulatingfluid flow includes: a fluid reservoir for infusing fluid containedtherein into a patient; a drip chamber in fluid communication with thefluid reservoir, wherein the drip chamber is configured to allow a dropof the fluid to exit the fluid reservoir and travel through the dripchamber; a backlight disposed near the drip chamber such that thebacklight provides at least partial illumination to the drip chamber; avalve configured to regulate the fluid flowing from the drip chamber tothe patient; and a flow meter for monitoring the flow rate of the fluidpassing through the drip chamber, the flow meter including: an imagesensor configured to capture an image of the drip chamber; a processorconfigured to determine whether the captured image of the drip chambercontains a match to a template; and a set of processor-executableinstructions configured to apply a blurring function to the imagecaptured by the image sensor of the drip chamber such that the processorcan determine if the captured image contains a match to the template.

The blurring function may be a low pass filter, the set ofprocessor-executable instructions configured to apply the low passfilter to the image captured by the image sensor in either a vertical ora horizontal direction. The low pass filter may include aone-dimensional Gaussian Blur function.

The blurring function may be a low pass filter, the set ofprocessor-executable instructions configured to apply the low passfilter to the image captured by the image sensor in both a vertical anda horizontal direction. The low pass filter includes a two-dimensionalGaussian Blur function. The template includes at least a partial imageof a drop of the fluid forming within the drip chamber. The capturedimage may include an image of the drip chamber that is at leastpartially illuminated by the backlight.

The desired pattern may include at least a partial image of a drop ofthe fluid forming within the drip chamber, the drop being at leastpartially illuminated by the backlight. The blurring function filtersthe captured image such that the processor can determine if the capturedimage contains a match to the template. The captured image is filteredto eliminate an amount of detail including images of at least one ofcondensation or splashes within the drip chamber.

In another embodiment, a method of filtering a captured image of a dripchamber configured to allow a drop of fluid to fall within the dripchamber, the method comprising: capturing an image of the drip chamberwith an image sensor; determining if the captured image contains avisual obstruction; applying a blurring function to the captured image,the blurring function configured to eliminate an amount of detail in thecaptured image; and determining if the captured image contains a matchto a template.

The desired pattern may includes at least a partial image of a drop offluid within the drip chamber. The blurring function may be a low passfilter, the low pass filter being applied in either a vertical directionor a horizontal direction. The low pass may filter includes aone-dimensional Gaussian Blur function. The blurring function may be alow pass filter, the low pass filter being applied in both a horizontaldirection and a vertical direction. The low pass filter may include atwo-dimensional Gaussian Blur function. The eliminated amount of detailmay include images of one of condensation or splashes within the dripchamber.

In another embodiment, a method of capturing an image of a drip chamber,the method comprising: illuminating at least a portion of a dripchamber; capturing an image of the drip chamber with an image sensor;determining if there is a visual obstruction in the captured image usinga processor operatively coupled to the image sensor; applying a blurringfunction, using the processor, to the captured image to filter thecaptured image upon a determination that there is a visual obstructionin the captured image; and determining, using the processor, if there isa match to a template in the captured image.

The template may include at least a partial image of a drop of fluidwithin the drip chamber. The blurring function may be is a low passfilter, the processor applying the low pass filter to the captured imagein either a horizontal direction or a vertical direction. The low passfilter may include a one-dimensional Gaussian Blur function. Theblurring function may be a low pass filter; the processor applying thelow pass filter to the captured image in both a horizontal direction anda vertical direction. The low pass filter may includes a two-dimensionalGaussian Blur function.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects will become more apparent from the followingdetailed description of the various embodiments of the presentdisclosure with reference to the drawings wherein:

FIG. 1 shows a block diagram of a system for regulating fluid flow inaccordance with an embodiment of the present disclosure;

FIG. 2 shows a flowchart diagram of a method for exposing an imagesensor in accordance with an embodiment of the present disclosure;

FIG. 3 shows a timing diagram illustrating an embodiment of the methodof FIG. 2 in accordance with an embodiment of the present disclosure;

FIGS. 4A-4B show illustrations of image data (i.e., images) captured bya flow meter of a drip chamber to illustrate an embodiment of the methodfor exposing an image sensor of FIG. 2 in accordance with the timingdiagram of FIG. 3 in accordance with an embodiment of the presentdisclosure;

FIG. 5 shows a diagram of a flow meter and valve that are integratedtogether for coupling to a drip chamber and an IV bag in accordance withan embodiment of the present disclosure;

FIG. 6 is a block diagram of an imaging system of a flow meter forimaging a drip chamber in accordance with an embodiment of the presentdisclosure;

FIG. 7 is a graphic illustration of an image captured by the imagesensor of the system of FIG. 6 in accordance with an embodiment of thepresent disclosure;

FIG. 8 is a block diagram of an imaging system of a flow meter forimaging a drip chamber utilizing a background pattern in accordance withan embodiment of the present disclosure;

FIG. 9 is a graphic illustration of an image captured by an image sensorof a flow meter disclosed herein when a free flow condition exists inaccordance with an embodiment of the present disclosure;

FIG. 10 is a graphic illustration of an image captured by an imagesensor of a flow meter for use as a background image in accordance withan embodiment of the present disclosure;

FIG. 11 is a graphic illustration of an image captured by an imagesensor when drops are being formed within a drip chamber in accordancewith an embodiment of the present disclosure;

FIG. 12 is a graphic illustration of an image captured by an imagesensor for use as a background image in accordance with an embodiment ofthe present disclosure;

FIG. 13 is a graphic illustration of a difference between the images ofFIGS. 11 and 12 with additional processing in accordance with anembodiment of the present disclosure;

FIG. 14 is a graphic representation of some of the image processingperformed using FIGS. 11-13 to determine if a free flow condition existsin accordance with an embodiment of the present disclosure;

FIG. 15 is a graphic illustration of an image captured by the imagesensor when a free flow condition exists in accordance with anembodiment of the present disclosure;

FIG. 16 is a graphic illustration of an image captured by the imagesensor for use as a background image in accordance with an embodiment ofthe present disclosure;

FIG. 17 is a graphic illustration of a difference between the images ofFIGS. 15 and 16 with some additional processing for use in detecting afree flow condition in accordance with an embodiment of the presentdisclosure;

FIG. 18 is a graphic representation of some of the image processingperformed using FIGS. 15-17 to determine if a free flow condition existsin accordance with an embodiment of the present disclosure;

FIG. 19 illustrates a template for pattern matching to determine if afree flow condition exits in accordance with an embodiment of thepresent disclosure;

FIG. 20 is a graphic illustration of a difference between a referenceimage and an image containing a stream processed with edge detection andline detection for use in detecting a free flow condition in accordancewith an embodiment of the present disclosure;

FIG. 21 is a graphic illustration of an image of a drip chamber capturedby an image sensor when a free flow condition exists in accordance withan embodiment of the present disclosure;

FIG. 22 is a block diagram of an imaging system for use with a flowmeter having a background pattern with stripes and a light sourceshining on the stripes from an adjacent location to an image sensor inaccordance with an embodiment of the present disclosure;

FIG. 23 is a block diagram of an imaging system for use with a flowmeter having a background pattern with stripes and a light sourceshining on the stripes from behind the background pattern relative to anopposite end of an image sensor in accordance with an embodiment of thepresent disclosure;

FIG. 24 illustrates an image from an image sensor when a drop distortsthe background pattern of FIG. 23 in accordance with an embodiment ofthe present disclosure;

FIG. 25 is a block diagram of an imaging system for use with a flowmeter having a background pattern with a checkerboard pattern and alight source shining on the stripes from behind the background patternrelative to an opposite end of an image sensor in accordance with anembodiment of the present disclosure;

FIG. 26 shows an image from the image sensor of FIG. 25 when a dropdistorts the background pattern in accordance with an embodiment of thepresent disclosure;

FIGS. 27-28 show a flow chart illustration of a method for estimating avolume of a drop within a drip chamber in accordance with an embodimentof the present disclosure;

FIGS. 29-31 illustrate images used or generated by a flow meter toestimate a volume of a drop within a drip chamber using the methodillustrated by FIGS. 27-28 in accordance with an embodiment of thepresent disclosure;

FIG. 32 shows pseudo code for identifying a plurality of pixels ofinterest in accordance with the method of FIGS. 27-28 in accordance withan embodiment of the present disclosure;

FIGS. 33-36 illustrate additional images used or generated by a flowmeter to estimate a volume of a drop within a drip chamber using themethod illustrated by FIGS. 27-28 in accordance with an embodiment ofthe present disclosure;

FIG. 37 shows pseudo code for determining a subset of pixels within theplurality of pixels of interest that corresponds to a drop in accordancewith an embodiment of the present disclosure;

FIG. 38 shows a ray diagram illustrating the diameter of a blur circleto illustrate aspects of an image sensor of an imaging system disclosedherein in accordance with an embodiment of the present disclosure;

FIG. 39 is a graphic illustrating a calculated blur circle for a varietyof lens-to-focal plane separations and lens-to-image separations for animage sensor of an imaging system disclosed herein in accordance with anembodiment of the present disclosure;

FIG. 40 is a graphic illustrating a blur circle divided by a pixel sizewhen a 20 millimeter focal length lens of an image sensor of an imagingsystem disclosed herein is used in accordance with an embodiment of thepresent disclosure;

FIG. 41 is a graphic illustrating a blur circle divided by a pixel sizewhen a 40 millimeter focal length lens of an image sensor of an imagingsystem disclosed herein is used in accordance with an embodiment of thepresent disclosure;

FIG. 42 shows a table illustrating the corresponding fields of viewabout the optical axis for the corners of two configurations of animaging system disclosed herein in accordance with an embodiment of thepresent disclosure;

FIG. 43 shows a flow meter coupled to a drip chamber in accordance withan embodiment of the present disclosure;

FIG. 44 shows the flow meter and drip chamber of FIG. 43 with the dooropen in accordance with an embodiment of the present disclosure;

FIG. 45 shows a flow meter coupled to a drip chamber in accordance withan embodiment of the present disclosure;

FIG. 46 shows a flow meter and a pinch valve coupled to the body of theflow meter to control the flow of fluid into a patient in accordancewith an embodiment of the present disclosure;

FIG. 47 shows a close-up view of the pinch valve that is coupled to thebody of the flow meter of FIG. 46 in accordance with an embodiment ofthe present disclosure;

FIG. 48 shows a flow meter and a pinch valve wherein the flow meterincludes two image sensors in accordance with another embodiment of thepresent disclosure;

FIG. 49 shows a flow meter and a valve including two curved, elongatedsupport members to control the flow of fluid into a patient inaccordance with an embodiment of the present disclosure;

FIGS. 50A-50B show close-up views of the valve of FIG. 49 in accordancewith an embodiment of the present disclosure;

FIGS. 51A-51D show several views of a flow meter with a monitoringclient, a valve, a drip chamber, an IV bag and a fluid tube wherein theflow meter includes a receiving portion to receive the valve inaccordance with an embodiment of the present disclosure;

FIGS. 52A-52D show several views of another flow meter with a valve, adrip chamber, and a tube wherein the flow meter has a receiving portionto receive the valve in accordance with an embodiment of the presentdisclosure;

FIG. 53A shows another view of the valve of FIGS. 51A-51D and 52A-52D inaccordance with an embodiment of the present disclosure;

FIGS. 53B-53C show two exploded views of the valve of FIG. 53A inaccordance with an embodiment of the present disclosure;

FIG. 54 shows the valve of FIG. 53 in manual use in accordance with anembodiment of the present disclosure;

FIG. 55 shows a valve that includes two flexible members in accordancewith an embodiment of the present disclosure;

FIGS. 56A-56C show several views of a valve having two curved, elongatedsupport members with one of the elongated support members having aplurality of ridges adapted to engage a tube in accordance with anembodiment of the present disclosure;

FIGS. 57A-57C show several views of a valve having a ratchet thatengages a connecting member in accordance with an embodiment of thepresent disclosure;

FIGS. 57D-57E show two exploded views of the valve of FIGS. 57A-57C inaccordance with an embodiment of the present disclosure;

FIGS. 58A-58D show several views of a valve having two elongated supportmembers, a connecting member, and a screw-type actuator in accordancewith another embodiment of the present disclosure;

FIGS. 59A-59C show several views of a body of a valve in accordance withan embodiment of the present disclosure;

FIGS. 59D-59G show several views of a knob for use with the body shownin FIGS. 59A-59C in accordance with an embodiment of the presentdisclosure;

FIG. 59H shows the assembled valve that includes the body shown in FIGS.59A-59C coupled to the knob of FIGS. 59D-59G in accordance with anembodiment of the present disclosure;

FIG. 60 shows a valve having a guiding protrusion in accordance with anembodiment of the present disclosure;

FIG. 61 shows a motor and a valve-securing structure for coupling to thevalve of FIG. 60 in accordance with an embodiment of the presentdisclosure;

FIG. 62 shows the valve of FIG. 60 secured to the motor and thevalve-securing structure of FIG. 61 in accordance with an embodiment ofthe present disclosure;

FIG. 63 shows another motor and valve-securing structure for coupling tothe valve of FIG. 60 in accordance with an embodiment of the presentdisclosure;

FIG. 64A shows a valve having a collar and several fingers forregulating fluid flow through a fluid line in accordance with anembodiment of the present disclosure;

FIG. 64B shows a cross-sectional view of the valve of FIG. 64A inaccordance with an embodiment of the present disclosure;

FIG. 65 shows a cross-sectional view of a valve having two curvedsurfaces for positioning a fluid tube therebetween to regulate fluidflow through the fluid tube in accordance with an embodiment of thepresent disclosure;

FIGS. 66A-66G show several views of a valve having a knob to move aconnecting member which is locked into position after movement of theknob in accordance with an embodiment of the present disclosure;

FIG. 67 shows a graphic that illustrates actuation vs. flow rates for avalve in accordance with an embodiment of the present disclosure;

FIG. 68A shows a flow meter that uses binary optics in accordance withan embodiment of the present disclosure;

FIG. 68B shows the circuit for use with FIG. 68A in accordance with anembodiment of the present disclosure;

FIGS. 69A-69I show several views of a safety valve that may be used witha flow meter in accordance with an embodiment of the present disclosure;

FIG. 70 shows a flow chart diagram illustrating a method of estimatingdrop growth and/or flow within a drip chamber in accordance with anembodiment of the present disclosure;

FIGS. 71A-71E show images taken by a flow meter with a template overlaidtherein to illustrate the method of FIG. 70 in accordance with anembodiment of the present disclosure;

FIG. 72 shows a modulatable backlight assembly in accordance with anembodiment of the present disclosure;

FIGS. 73A-73C show several views of a tube-restoring apparatus inaccordance with an embodiment of the present disclosure;

FIG. 74 shows a system for regulating fluid flow using a valve havingtwo flexible strips in accordance with an embodiment of the presentdisclosure;

FIG. 75 shows the valve of FIG. 74 in accordance with an embodiment ofthe present disclosure;

FIG. 76A shows a valve that utilizes a fluid-based bladder in accordancewith an embodiment of the present disclosure;

FIG. 76B shows a cross-sectional view of the assembled valve of FIG. 76Awith two elastomeric fillers in accordance with an embodiment of thepresent disclosure;

FIG. 77 shows a system for regulating fluid flow using a valve havingtwo flexible strips actuatable by a linear actuator in accordance withan embodiment of the present disclosure;

FIG. 78 shows the system of FIG. 77 with the valve actuated inaccordance with an embodiment of the present disclosure;

FIG. 79 shows a close-up view of the valve of FIGS. 77-78 in accordancewith an embodiment of the present disclosure;

FIG. 80 shows a close-up view of the valve as actuated in FIG. 78 inaccordance with an embodiment of the present disclosure;

FIG. 81 shows several images for use to illustrate a method ofestimating drop growth and/or fluid flow illustrated in FIGS. 82A-82B inaccordance with an embodiment of the present disclosure; and

FIGS. 82A-82B show a flow chart diagram illustrating a method ofestimating drop growth and/or fluid flow in accordance with anembodiment of the present disclosure;

FIG. 83 shows a flow chart diagram of a method for reducing noise fromcondensation in accordance with an embodiment of the present disclosure;

FIG. 84 shows another valve for use with a flow meter in accordance withan embodiment of the present disclosure;

FIG. 85A shows a perspective view of another valve in an open positionin accordance with an embodiment of the present disclosure;

FIG. 85B shows a perspective view of the valve of FIG. 85A in a closedposition in accordance with an embodiment of the present disclosure;

FIG. 85C shown a view of the valve of FIG. 85A with the valve housingand plunger guide removed in accordance with an embodiment of thepresent disclosure;

FIG. 86 shows a cross-sectional view of the valve housing of FIGS.85A-85C and filler when in a closed position in accordance with anembodiment of the present disclosure;

FIG. 87A show a front view of an apparatus with the door closed, theapparatus is used to control fluid flow through a drip chamber connectedto a tube in accordance with an embodiment of the present disclosure;

FIG. 87B shows a perspective view of the apparatus of FIG. 87A with thedoor open, highlighting the valve in accordance with an embodiment ofthe present disclosure;

FIG. 87C shows a perspective view of the apparatus of FIG. 87A with thedoor open, highlighting the safety cutoff mechanism in accordance withan embodiment of the present disclosure;

FIG. 87D shows a bottom view of the apparatus of FIG. 87A in accordancewith an embodiment of the present disclosure;

FIG. 88A shows a perspective view of another apparatus used to controlfluid flow through a drip chamber connected to a tube, wherein theapparatus has the door open, in accordance with an embodiment of thepresent disclosure;

FIG. 88B shows a perspective view of only the valve from FIG. 88A inaccordance with an embodiment of the present disclosure;

FIG. 88C shows the inner workings of the valve from FIG. 88B inaccordance with an embodiment of the present disclosure;

FIG. 88D shows a simplified diagram illustrate the operation of thevalve cutoff mechanism in a door closed position in accordance with anembodiment of the present disclosure;

FIG. 88E shows a simplified diagram to illustrate the valve cutoffmechanism in the door open position in accordance with an embodiment ofthe present disclosure;

FIGS. 89A-89B show a flow chart diagram of a method for controllingfluid flow through a drip chamber in accordance with an embodiment ofthe present disclosure;

FIG. 90 shows a diagram of a system for controlling fluid flow through adrip chamber; and

FIG. 91 shows an apparatus configured to control fluid flow through adrip chamber connected to a tube and communicate with an RFIDinterrogator in accordance with an embodiment of the present disclosure.

FIG. 92 shows an obstructed drip chamber that may render difficult theobtainment of an accurate image of the drip chamber by an image sensor.

FIG. 93 shows a flow chart diagram of a method for obtaining an image ofa drip chamber.

FIG. 94 shows a graphical representation of drops, as seen by an imagesensor, as each drop grows within a drip chamber and subsequently falls.

FIG. 95 shows a graphical representation of a system to convey thestatus of a device.

DETAILED DESCRIPTION

FIG. 1 shows a block diagram of a system 1 for regulating fluid flow inaccordance with an embodiment of the present disclosure. For example,system 1 may regulate, monitor, and/or control the flow of fluid into apatient 3. The system 1 includes a fluid reservoir 2 for infusing fluidcontained therein into the patient 3. The fluid reservoir 2 is gravityfed into a drip chamber 4 via a fluid tube 5. The fluid reservoir 2, thedrip chamber 4, and the patient 3 may be considered as part of thesystem 1 or may be considered as separate or optional work pieces forthe system 1 (e.g., any fluid reservoir 2 and drip chamber 4 may be usedto treat any patient 3).

A flow meter 7 monitors the drip chamber 4 to estimate a flow rate ofliquid flowing through the drip chamber 4. The fluid from the dripchamber 4 is gravity fed into a valve 6. The valve 6 regulates (i.e.,varies) the flow of fluid from the fluid reservoir 2 to the patient 3 byregulating fluid flow from the drip chamber 4 to the patient 3. Thevalve 6 may be any valve as described herein, including a valve havingtwo curved-shaped members, a valve having two flexible sheets, a valvethat pinches (or uniformly compresses) on the tube over a significantlength of the tube, or the like. The valve 6 may be aninverse-Bourdon-tube valve that works in an opposite way of a Bourdontube in that a deformation of the fluid path causes changes in fluidflow rather than fluid flow causing deformation of the fluid path.

In alternative embodiments, the system 1 optionally includes an infusionpump 414 (e.g., a peristaltic pump, a finger pump, a linear peristalticpump, a rotary peristaltic pump, a cassette-based pump, a membrane pump,other pump, etc.) coupled to the fluid tube 5. The outlined boxdesignated as 414 represents the optional nature of the infusion pump414, e.g., the infusion pump may not be used in some embodiments. Theinfusion pump 414 may use the flow meter 7 as feedback to control theflow of fluid through the fluid tube 5. The infusion pump 414 may be inwireless communication with the flow meter 7 to receive the flow ratetherefrom. The infusion pump 414 may use a feedback control algorithm(e.g., the control component 14 of FIG. 1) to adjust the flow of fluid,such as a proportional-integral-derivative (“PID”), bang-bang, neuralnetwork, and/or fuzzy logic control system. In this specific exemplaryembodiment (i.e., an embodiment having the infusion pump 414), the valve6 is optional. However, in other embodiments, the valve 6 may or may notbe used, and/or is optional. The infusion pump 414 may adjust therotation of a cam and/or a motor in accordance with measurements fromthe flow meter 7, such as flow rate, volume infused, total volumeinfused, etc. Additionally or alternatively, the infusion pump 414 maystop fluid flow (e.g., by stopping the pumping action) when the flowmeter 7 communicates to the infusion pump 414 that a free flow conditionexists. In yet additional embodiments, the monitoring client 8 controlsthe operation of the infusion pump 414 (e.g., via a wireless connection)and receives feedback from the flow meter 7.

In some embodiments, the fluid reservoir 2 is pressurized to facilitatethe flow of fluid from the fluid reservoir 2 into the patient 3, e.g.,in the case where the fluid reservoir 2 (e.g., an IV bag) is below thepatient 3; The pressurization provides sufficient mechanical energy tocause the fluid to flow into the patient 3. A variety of pressuresources, such as physical pressure, mechanical pressure, and pneumaticpressure may be applied to the inside or outside of the fluid reservoir2. In one such embodiment, the pressurization may be provided by arubber band wrapped around an IV bag.

The flow meter 7 and the valve 6 may form a closed-loop system toregulate fluid flow to the patient 3. For example, the flow meter 7 mayreceive a target flow rate from a monitoring client 8 by communicationusing transceivers 9, 10. That is, the transceivers 9, 10 may be usedfor communication between the flow meter 7 and the monitoring client 8.The transceivers 9, 10 may communicate between each other using amodulated signal to encode various types of information such as digitaldata or an analog signal. Some modulation techniques used may includeusing carrier frequency with FM modulation, using AM modulation, usingdigital modulation, using analog modulation, or the like.

The flow meter 7 estimates the flow rate through the drip chamber 4 andadjusts the valve 6 to achieve the target flow rate received from themonitoring client 8. The valve 6 may be controlled by the flow meter 7directly from communication lines coupled to an actuator of the valve 6or via a wireless link from the flow meter 7 to onboard circuitry of thevalve 6. The onboard electronics of the valve 6 may be used to controlactuation of the valve 6 via an actuator coupled thereto. Thisclosed-loop embodiment of the flow meter 7 and the valve 6 may utilizeany control algorithm including a PID control algorithm, a neuralnetwork control algorithm, a fuzzy-logic control algorithm, the like, orsome combination thereof.

The flow meter 7 is coupled to a support member 17 that is coupled tothe drip chamber 4 via a coupler 16. The support member 17 also supportsa backlight 18. The backlight 18 includes an array of LEDs 20 thatprovides illumination to the flow meter 7. In some specific embodiments,the backlight 18 includes a background pattern 19. In other embodiments,the backlight 18 does not include the background pattern 19. In someembodiments, the background pattern 19 is present in only the lowerportion of the backlight 18 and there is no background pattern 19 on thetop (e.g., away from the ground) of the backlight 18.

The flow meter 7 includes an image sensor 11, a free flow detectorcomponent 12, a flow rate estimator component 13, a control component14, an exposure component 29, a processor 15, and a transceiver 9. Theflow meter 7 may be battery operated, may be powered by an AC outlet,may include supercapacitors, and may include on-board, power-supplycircuitry (not explicitly shown).

The image sensor 11 may be a CCD sensor, a CMOS sensor, or other imagesensor. The image sensor 11 captures images of the drip chamber 4 andcommunicates image data corresponding to the captured images to theprocessor 15.

The processor 15 is also coupled to the free flow detector component 12,the flow rate estimator component 13, the control component 14, and theexposure component 29. The free flow detector component 12, the flowrate estimator component 13, the control component 14, and the exposurecomponent 29 may be implemented as processor-executable instructionsthat are executable by the processor 15 and may be stored in memory,such as a non-transitory, processor-readable memory, ROM, RAM, EEPROM, aharddisk, a harddrive, a flashdrive, and the like.

The processor 15 can execute the instructions of the free flow detectorcomponent 12 to determine if a free flow condition exists within thedrip chamber 4 by analyzing the image data from the image sensor 11.Various embodiments of the free flow detector component 12 for detectinga free flow condition are described below. In response to a detectedfree flow condition, the processor 15 can make a function call to thecontrol component 14 to send a signal to the valve 6 to completely stopfluid flow to the patient 3. That is, if the free flow detectorcomponent 12 determines that a free flow condition exists, the flowmeter 7 may instruct the valve 6 to stop fluid flow, may instruct themonitoring client 8 to stop fluid flow (which may communicate with thevalve 6 or the pump 414), and/or may instruct the pump 414 to stoppumping or occlude fluid flow using an internal safety occluder.

The flow rate estimator component 13 estimates the flow rate of fluidflowing through the drip chamber 4 using the image data from the imagesensor 11. The processor 15 communicates the estimated flow rate to thecontrol component 14 (e.g., via a function call). Various embodiments ofestimating the flow rate are described below. If the flow rate estimatorcomponent 13 determines that the flow rate is greater than apredetermined threshold or is outside a predetermined range, the flowmeter 7 may instruct the valve 6 to stop fluid flow (which maycommunicate with the valve 6 or the pump 414), may instruct themonitoring client 8 to stop fluid flow (which may communicate with thevalve 6 or the pump 414), and/or may instruct the pump 414 to stoppumping or occlude fluid flow using an internal safety occluder.

The processor 15 controls the array of LEDs 20 to provide sufficientlight for the image sensor 11. For example, the exposure component 29may be used by the processor 15 or in conjunction therewith to controlthe array of LEDs 20 such that the image sensor 11 captures image datasufficient for use by the free flow detector component 12 and the flowrate estimator component 13. The processor 15 may implement an exposurealgorithm stored by the exposure component 29 (see FIG. 2) to controlthe lighting conditions and/or the exposure of the image sensor 11 whengenerating the image data. Additionally or alternatively, the exposurecomponent 29 may be implemented as a circuit, an integrated circuit, aCPLD, a PAL, a PLD, a hardware-description-language-basedimplementation, and/or a software system.

The control component 14 calculates adjustments to make to the valve 6in accordance with the estimated flow rate from the flow rate estimatorcomponent 13. For example and as previously mentioned, the controlcomponent 14 may implement a PID control algorithm to adjust the valve 6to achieve the target flow rate.

The monitoring client 8, in some embodiments, monitors operation of thesystem 1. For example, when a free flow condition is detected by thefree flow detector component 12, the monitoring client 8 may wirelesslycommunicate a signal to the valve 6 to interrupt fluid flow to thepatient 3.

The flow meter 7 may additionally include various input/output devicesto facilitate patient safety, such as various scanners, and may utilizethe transceiver 9 to communicate with electronic medical records, drugerror reduction systems, and/or facility services, such as inventorycontrol systems.

In a specific exemplary embodiment, the flow meter 7 has a scanner, suchas an RFID interrogator that interrogates an RFID tag attached to thefluid reservoir 2 or a barcode scanner that scans a barcode of the fluidreservoir 2. The scanner may be used to determine whether the correctfluid is within the fluid reservoir 2, it is the correct fluid reservoir2, the treatment programmed into the flow meter 7 corresponds to thefluid within the fluid reservoir 2 and/or the fluid reservoir 2 and flowmeter 7 are correct for the particular patient (e.g., as determined froma patient's barcode, a patient's RFID tag, or other patientidentification).

For example, the flow meter 7 may scan the RFID tag of the fluidreservoir 2 to determine if a serial number or fluid type encoded withinthe RFID tag is the same as indicated by the programmed treatment storedwithin the flow meter 7. Additionally or alternatively, the flow meter 7may interrogate the RFID tag of the fluid reservoir 2 for a serialnumber and the RFID tag of the patient 3 for a patient serial number,and also interrogate the electronic medical records using thetransceiver 9 to determine if the serial number of the fluid reservoir 2within the RFID tag attached to the fluid reservoir 2 matches thepatient's serial number within the RFID tag attached to the patient 3 asindicated by the electronic medical records.

Additionally or alternatively, the monitoring client 8 may scan the RFIDtag of the fluid reservoir 2 and the RFID tag of the patient 3 todetermine that it is the correct fluid within the fluid reservoir 2, itis the correct fluid reservoir 2, the treatment programmed into the flowmeter 7 corresponds to the fluid within the fluid reservoir 2, and/orthe fluid reservoir 2 is correct for the particular patient (e.g., asdetermined from a patient's barcode, RFID tag, electronic medicalrecords, or other patient identification or information). Additionallyor alternatively, the monitoring client 8 or the flow meter 7 mayinterrogate the electronic medical records database and/or the pharmacyto verify the prescription or to download the prescription, e.g., usingthe serial number of the barcode on the fluid reservoir 2 or the RFIDtag attached to the fluid reservoir 2.

FIG. 2 shows a flow chart diagram of a method 21 for exposing an imagesensor, e.g., the image sensor 11 of FIG. 1, in accordance with anembodiment of the present disclosure. The method 21 includes acts 22,23, 24, and 25. Method 21 may be implemented by the processor 15 of FIG.1 (e.g., as the exposure component 29) and may be implemented as aprocessor-implemented method, as a set of instructions configured forexecution by one or more processors, in hardware, in software, the like,or some combination thereof.

Act 22 selects a region of interest. For example, referring again toFIG. 1, the image sensor 11 includes a field of view that includes thedrip chamber 4. However, the drip chamber 4 may not occupy the entirefield of view of the image sensor 11. Act 22 selects only the pixels ofthe image sensor 11 that show, for example, the drip chamber 4.

Act 23 determines if a pixel is within the region of interest 23. If thepixel of act 23 is a pixel that images, for example, the drip chamber 4,then act 23 determines that it is within the region of interest.Likewise, in this example, if the pixel of act 23 is a pixel that doesnot image the drip chamber 4, act 23 determines that the pixel is notwithin the region of interest.

Act 24 activates a backlight, e.g., the backlight 18 of FIG. 1, if thepixel is within the region of interest. Pixels of an image sensor may beexposed during different times. Thus, the backlight 18 may be activatedonly when pixels within the region of interest are being exposed. Forexample, some image sensors include vertical and horizontal syncsignals. The backlight may be synchronized with these signals to turn onwhen a pixel of interest is being exposed.

In some embodiments of the present disclosure, a subset of LEDs of thebacklight (e.g., a subset of the LED array 20, which may be a2-dimensional array) may be turned on. The subset may be a sufficientsubset to sufficiently illuminate the pixel being exposed if the pixelis within the region of interest.

Act 25 exposes the pixel. If in act 23 it was determined that the pixelis within the region of interest, the pixel will be exposed with atleast a portion of the backlight turned on in act 25. Additionally, ifin act 23 it was determined that the pixel is not within the region ofinterest, the pixel will be exposed without at least a portion of thebacklight turned on in act 25.

FIG. 3 shows a timing diagram 29 illustrating an embodiment of themethod of FIG. 2 in accordance with an embodiment of the presentdisclosure. The timing diagram 29 includes traces 26, 27, and 28. Trace26 is a vertical sync signal from an image sensor and trace 27 is ahorizontal sync signal from the image sensor (e.g., image sensor 11 ofFIG. 1). A circuit or software routine (e.g., the exposure component 29found in the flow meter 7 of FIG. 1) may use the sync traces 26, 27 togenerate a backlight-enable signal 28 that is used to activate abacklight or a subset thereof.

FIGS. 4A-4B show illustrations of image data of a flow meter 7illustrating an embodiment of the method of FIG. 2 in accordance withthe timing diagram of FIG. 3 in accordance with an embodiment of thepresent disclosure. FIG. 4A illustrates the image data taken by a flowmeter, such as the flow meter 7 of FIG. 1, without the use of theexposure algorithm illustrated in FIGS. 2 and 3; FIG. 4B illustrates theimage data taken by the flow meter with the use of the exposurealgorithm illustrated in FIGS. 2 and 3. Less power is needed to provideillumination during the capture of the image of FIG. 4B than to provideillumination for the capture of the image of FIG. 4A because of less useof the backlight.

FIG. 5 shows a diagram of a flow meter 67 and a valve 71 that areintegrated together for coupling to a drip chamber 409 and an IV bag 69in accordance with an embodiment of the present disclosure. The flowmeter 67 includes an optical drip counter 68 that receives fluid fromthe IV bag 69. The optical drip counter 68 may be an image sensor, apair of image sensors, a capacitive drip counter, and/or the like. Theflow meter 67 is coupled to a tube 70 coupled to a roller clamp 71 thatis controlled by a motor 72. The motor 72 is coupled to a lead screwmechanism 73 to control a roller clamp 71 via interaction withinteracting members 74.

The motor 72 may be a servo motor and may be used to adjust the flowrate through the tube 70. That is, the flow meter 67 may also functionas a flow meter and regulator. For example, a processor 75 within theflow meter 67 may adjust the motor 72 such that a desired flow rate isachieved as measured by the optical drip counter 68. The processor 75may implement a control algorithm using the optical drip counter 68 asfeedback, e.g., a PID control loop with the output supplied to the motor72 and the feedback received from the optical drip counter 68.

In alternative embodiments, the motor 72, the lead screw mechanism 73,and the roller clamp 71 may be replaced and/or supplemented by anactuator that squeezes the tube 70 (e.g., using a cam mechanism orlinkage driven by a motor) or they may be replaced by any sufficientroller, screw, or slider driven by a motor. For example, in someembodiments of the present disclosure, the roller clamp 71 may bereplaced by any valve as described herein, including a valve having twoC-shaped members, a valve having two curve-shaped support members, avalve having two flexible sheets, a valve that pinches on the tube overa significant length of the tube, or the like.

The flow meter 67 may also optionally include a display. The display maybe used to set the target flow rate, display the current flow rate,and/or provide a button, e.g., a touch screen button to stop the flowrate.

FIG. 6 is a block diagram of an imaging system 78 of a flow meter forimaging a drip chamber in accordance with an embodiment of the presentdisclosure. The imaging system 78 as shown in FIG. 6 may be used withinany flow meter described herein, including the flow meter 7 of FIG. 1and/or the flow meter 67 of FIG. 5.

The imaging system 78 of FIG. 6 includes an image sensor 63, a uniformbacklight 79 to shine light at least partially through the drip chamber59, and an infrared (“IR”) filter 80 that receives the light from theuniform backlight 79.

System 78 also includes a processor 90 that may be operatively coupledto the image sensor 63 and/or the uniform backlight 79. The processor 90implements an algorithm to determine when a free flow condition existsand/or to estimate a flow rate (e.g., using the free flow detectorcomponent 12 or the flow rate estimator component 13 of FIG. 1). Theprocessor 90 may be in operative communication with a processor-readablememory 91 (e.g., a non-transitory, processor-readable memory) to receiveone or more instructions to implement the algorithm to determine if afree flow condition exists and/or to estimate the flow rate. The one ormore instructions from the processor-readable memory 91 are configuredfor execution by the processor 90.

The uniform backlight 79 may be an array of light-emitting diodes(“LEDs”) having the same or different colors, a light bulb, a window toreceive ambient light, an incandescent light, and the like. In someembodiments, the uniform backlight 79 may include one or morepoint-source lights.

The processor 90 may modulate the uniform backlight 79 in accordancewith the image sensor 63. For example, the processor 90 may activate theuniform backlight 79 for a predetermined amount of time and signal theimage sensor 63 to capture at least one image, and thereafter signal theuniform backlight 79 to turn off. The one or more images from the imagesensor 63 may be processed by the processor 90 to estimate the flow rateand/or detect free flow conditions. For example, in one embodiment ofthe present disclosure, the system 78 monitors the size of the dropsbeing formed within the drip chamber 59, and counts the number of dropsthat flow through the drip chamber 59 within a predetermined amount oftime; the processor 90 may average the periodic flow from the individualdrops over a period of time to estimate the flow rate. For example, if Xdrops each having a volume Y flow through the drip chamber in a time Z,the flow rate may be calculated as (X*Y)/Z.

Additionally or alternatively, the system 78 may determine when the IVfluid is streaming through the drip chamber 59 (i.e., during a free flowcondition). The uniform backlight 79 shines light through the dripchamber 59 to provide sufficient illumination for the image sensor 63 toimage the drip chamber 59. The image sensor 63 can capture one or moreimages of the drip chamber 59.

Other orientations and configurations of the system 78 may be used toaccount for the orientation and output characteristics of the uniformbacklight 79, the sensitivity and orientation of the image sensor 63,and the ambient light conditions. In some embodiments of the presentdisclosure, the processor 90 implements an algorithm that utilizes auniformity of the images collected by the image sensor 63. Theuniformity may be facilitated by the uniform backlight 79. For example,consistent uniform images may be captured by the image sensor 63 when auniform backlight 79 is utilized.

Ambient lighting may cause inconsistencies in the images received fromthe image sensor 63; for example, direct solar illumination providesinconsistent lighting because the sun may be intermittently obscured byclouds and the sun's brightness and angle of illumination depend uponthe time of the day. Therefore, in some embodiments of the presentdisclosure, an IR filter 80 is optionally used to filter out some of theambient light to mitigate variations in the images captured by the imagesensor 63. The IR filter 80 may be a narrow-band infrared light filterplaced in front of the image sensor 63; and the uniform backlight 79 mayemit light that is about the same wavelength as the center frequency ofthe passband of the filter 80. The IR filter 80 and the uniformbacklight 79 may have a center frequency of about 850 nanometers. Insome embodiments, the imaging system 78 may be surrounded by a visuallytranslucent, but IR-blocking, shell. In alternative embodiments, otheroptical frequencies, bandwidths, center frequencies, or filter types maybe utilized in the system 78.

In some embodiments, the processor 90 may use a template to perform atemplate match of the pool of water within the drip chamber 59. Anypreprocessing may be performed prior to the template match operation.Additionally, if the camera 63 is disposed higher than a preferredposition, a minor may be used so that the camera's 63 view is of apreferable view of the drip chamber 59. The position of the peaktemplate match may be correlated to the pool's position and hence thepool's volume.

If the pool is too low, the apparatus may trigger a safety valve(described below) because water is leaving the pool and is drainingtoward the patient at an unsafe rate. The backlight 79 may be on or off,depending on the embodiment. The oscillations of the top of the pool maybe monitored to determine the resonance frequency of the water. Theresonance of the top of the pool as the drops hit the pool may becorrelated with the volume of the pool. In other embodiments, the suddenchange of the pool may be correlated with a drop hitting the pool suchthat the processor 90 can count the number of drops per unit time andestimate the fluid flow therethrough.

In some embodiments, autofocus may be used to find the line of water.That is, a focal line may be focused to ensure the entire image isfocused.

In some embodiments, the processor 90 may be coupled to a wire etchedonto a PCB board making it a software radio. This allows the processor90 to communicate information to another device capable of operating atthe sufficient frequencies.

FIG. 7 is a graphic illustration of an image 81 captured by the imagesensor 63 of the system 78 of FIG. 6 in accordance with an embodiment ofthe present disclosure. The image 81 is an image of a drip chamber 59having condensation 82 and a stream 83 caused by a free flow conditiontherein. Edge detection may be used to determine the position of thestream 83 and/or the condensation 82, in some embodiments. Additionallyor alternatively, a background image or pattern may be used.

FIG. 8 is a block diagram of an imaging system 84 of a flow meter forimaging a drip chamber in accordance with an embodiment of the presentdisclosure. The imaging system 84 may be used with any flow meterdisclosed herein, including the flow meter 7 of FIG. 1 and the flowmeter 67 of FIG. 5.

System 84 includes an array of lines 85 that are opaque behind the dripchamber 59. System 84 uses the array of lines 85 to detect a free flowcondition. The free flow detection algorithm (e.g., the free flowdetector component 12 of FIG. 1) may use the presence or absence ofdrops for determining whether or not a streaming condition (e.g., a freeflow condition) exists.

In some specific embodiments, the lines 85 are only present on afraction of the image (e.g., the background pattern only occupies afraction of the backlight 18 or the binary optics only causes thepattern to appear in a fraction of the image, such as the lower or upperhalf). For example, a lower fraction of the image may include abackground pattern of stripes.

Referring now to FIG. 9, a graphic illustration of an image 86 is shownas captured by the image sensor 63 of FIG. 8 when a free flow conditionexists in the drip chamber 59 in accordance with an embodiment of thepresent disclosure. The image 86 illustrates the condition in which thedrip chamber 59 experiences a free flow condition and illustrates theeffect that the stream of fluid 87 acts as a positive cylindrical lens.That is, as shown in FIG. 9, the array of lines 85 as captured in animage by the image sensor 63 are shown as a reversed line pattern 88from the array of lines 85 as compared to a non-free flow condition. Theappearance of the reversed line pattern 88 is caused by changes to thelight when the light passes through the stream of fluid 87 as the lightapproaches the image sensor 63.

In some embodiments of the present disclosure, illumination by lighthaving an optical wavelength of about 850 nanometers may be used tocreate the image 86. Some materials may be opaque in the visiblespectrum and transparent in the near IR spectrum at about 850 nanometersand therefore may be used to create the array of lines 85. The array oflines 85 may be created using various rapid-prototyping plastics. Forexample, the array of lines 85 may be created using a rapid-prototypestructure printed with an infrared-opaque ink or coated with a metal formaking the array of lines 85. Additionally or alternatively, in someembodiments of the present disclosure, another method of creating thearray of lines 85 is to create a circuit board with the lines laid downin copper. In another embodiment, the array of lines 85 is created bylaying a piece of ribbon cable on the uniform backlight 79; the wires inthe ribbon cable are opaque to the infrared spectrum, but the insulationis transparent such that the spacing of the wires may form the line foruse during imaging by the image sensor 63 (see FIG. 8). In yetadditional embodiments, a piece of thin EDMed metal may be utilized.Metal is opaque to light and the spaces between the metal materialdeposits may be very finely controlled during manufacture to allow theIR light to pass through the spaces.

The processor 90 implements an algorithm to determine when a free flowcondition exists (e.g., using the free flow detector component 12 ofFIG. 1). The processor 90 may be in operative communication with aprocessor-readable memory 91 (e.g., a non-transitory, processor-readablememory) to receive one or more instructions to implement the algorithmto determine if a free flow condition exists. The one or moreinstructions from the processor-readable memory 91 are configured forexecution by the processor 90.

Referring again to FIG. 8, blood may be used by the system 84. Forexample, system 84 may determine when a free flow condition of bloodexists when utilizing the image sensor 63, the IR filter 80, and theuniform backlight 79 configured, for example, for use using opticallight having a wavelength of 850 nanometers or 780 nanometers, e.g.,when using bovine blood. The blood may appear opaque compared to theimages taken using water.

The following algorithm implemented by the processor 90 and receivedfrom the processor-readable memory 91 may be used to determine when afree flow condition exists: (1) establish a background image 89 (seeFIG. 10); and (2) subtract the background image 89 from the currentimage. Additionally processing may be performed on the resulting image.

In some embodiments of the present disclosure, the background image 89of FIG. 10 may be dynamically generated by the processor 90. The dynamicbackground image may be used to account for changing conditions, e.g.condensation or splashes 82 on the surface of the drip chamber 59 (seeFIG. 7). For example, in one specific embodiment, for each new imagecaptured by the image sensor (e.g., 63 of FIG. 8), the background imagehas each pixel multiplied by 0.96 and the current image (e.g., the mostrecently captured image) has a respective pixel multiplied by 0.04,after which the two values are added together to create a new value fora new background image for that respective pixel; this process may berepeated for all of the pixels. In yet another example, in one specificembodiment, if a pixel of the new image is at a row, x, and at a column,y, the new background image at row, x, and column, y, is the value ofthe previous background image at row, x, and column, y, multiplied by0.96, which is added to the value of the pixel at row, x, and column, yof the new image multiplied by 0.04.

When the system 84 has no water flowing through the drip chamber 59 (seeFIG. 8) the resulting subtraction should be almost completely back,i.e., low pixel magnitudes, thereby facilitating the algorithm todetermine that the drip chamber 59 has no water flowing therethrough.

FIG. 11 shows an image 92 from the image sensor 63 when there is a dropwithin the drip chamber 59 (see FIG. 8). FIG. 12 shows a backgroundimage 93 used by the system 84. When the system 84 has a drop as shownin image 92 of FIG. 11, the system 84 of FIG. 8 has a few highcontrast-spots where the image of the array of lines is warped by thelensing of the droplet as illustrated by an image 94 of FIG. 13. Image94 of FIG. 13 is generated by taking, for each respective pixel, theabsolute value of the subtraction of the image 92 of FIG. 11 from image93 of FIG. 12, and converting each respective pixel to a white pixel ifthe value is above a predetermined threshold or otherwise converting thepixel to a black pixel when the value is below the predeterminedthreshold. Each white pixel within the image 94 of FIG. 13 is a resultof there being a difference for that pixel location between the images92 and 93 that is greater than a predetermined threshold.

For example, consider three respective pixels of FIGS. 11, 12, and 13having a location of row x and column y. To determine the pixel of row xand column y for the image 94 of FIG. 13, the pixel at row x and columny of image 92 of FIG. 11 is subtracted from the pixel at row x andcolumn y of image 93 of FIG. 12, then the absolute value of the resultof the subtraction is taken; and if the absolute value of the result isabove a predetermined threshold (e.g., above a grayscale value of 128,for example), the pixel at the location of row x and column y of image94 of FIG. 13 is white, otherwise the pixel at the location of row x andcolumn y of image 94 of FIG. 13 is black.

When it is determined that a few high-contrast spots exist within theimage 94 of FIG. 13, the processor 90 of system 84 (see FIG. 8)determines that drops are being formed within the drip chamber 59 and nofree flow condition exists. The images of the drops may be utilized todetermine the size of the drops to estimate a flow rate as describedherein.

FIG. 14 is a graphic representation of some of the image processing thatmay be performed using FIGS. 11-13 to determine if a free flow conditionexists in accordance with an embodiment of the present disclosure.Referring to FIGS. 14 and 13, all of the white pixels for each row aresummed together, and are illustrated in FIG. 14 as results 183. They-axis represents the row number, and the x-axis represents the summednumber of white pixels for each respective row.

Referring now to only FIG. 14, as previously mentioned, the number ofwhite pixels for each row is summed together and is illustrated asresults 183, which are used to determine if or when a free flowcondition exists. In some specific embodiments, the processor 90 ofsystem 84 (see FIG. 8) determines that a free flow condition exists whena predetermined number of contiguous values of the summed rows of theresults 183 exists above a threshold 184. For example, within theresults 183, a range of a plurality of contiguous rows representedgenerally by 185 has a total value above the threshold 184. When greaterthan a predetermined number of contiguous summed rows is determined toexist within the results 183 above a predetermined threshold (e.g.,threshold 184), a free flow condition is determined to exist by theprocessor 90 of FIG. 8. For example, as shown in FIG. 14, the range ofthe plurality of contiguous summed rows 185 is below the predeterminednumber of contiguous summed rows (i.e., the range 185 is not wideenough) and therefore a free flow condition is determined to not exist.

FIG. 15 shows an image 95 showing a stream as captured by the imagesensor 63 of FIG. 8 when a free flow condition exists. FIG. 16 shows abackground image 96. FIG. 17 shows an image 97 formed by the absolutevalue of the difference between the image 96 of FIG. 16 and the image 95from FIG. 15 when the absolute value is converted either to a whitepixel (when the absolute value of the difference is above a threshold)or to a black pixel (when the absolute value of the difference is belowthe threshold). As shown in FIG. 17, high-contrast spots caused by thereverse orientation of the lines in the stream that run from top tobottom are detectable by the processor 90. The processor 90 of FIG. 8can use the image 97 to determine if a free flow condition exists usingthe algorithm described above.

That is, as shown in FIG. 18, results 186 are shown as having acontiguous range 187 of the results 186 that are above a threshold 188.Because the contiguous range 187 of summed rows is greater than apredetermined threshold number of contiguous values above the threshold188, a free flow condition is determined to exist by the processor 90(see FIG. 8). That is, the contiguous range of the results 186 above thethreshold 188 is greater than a predetermined threshold range ofcontiguous values; therefore, the processor 90 determines that a freeflow condition exists when using the results 186 of FIG. 18.

In yet an additional embodiment of the present disclosure, theintensity, the intensity squared, or other function may be used toproduce the results 183 of FIG. 14 and/or the results 186 of FIG. 18. Inyet an additional embodiment, one or more data smoothing functions maybe used to smooth the results 183 and/or 186, such as a spline function,a cubic spline function, a B-spline function, a Bezier spline function,a polynomial interpolation, a moving average, or other data smoothingfunction.

For example, an image of the image sensor 63 of FIG. 8, e.g., image 95of FIG. 15, may be subtracted from a background image, e.g., the image96 of FIG. 16, to obtain intensity values. That is, a pixel of row x andcolumn y of FIG. 15 may be subtracted from a pixel of row x and column yof the image 96 of FIG. 16 to create an intensity value at row x andcolumn y; this may be repeated for all pixel locations to obtain all ofthe intensity values. The intensity values of each row may be summedtogether to obtain the results 183 and/or 186 (see FIGS. 14 and 18,respectively), such that the processor 90 may determine that a free flowcondition exists when the summed rows of the intensity values has acontiguous range of summed rows above a threshold. In some embodiments,the intensity values are converted to absolute values of the intensityvalues, and the summed rows of the absolute values of the intensityvalues are used to determine if a contiguous range of summed rows of theabsolute values is above a threshold range of contiguous values.Additionally or alternatively, the intensity may be squared and then theprocessor 90 may sum the squared intensity rows and determine if acontiguous range of summed rows of the intensity squared values existsbeyond a threshold range of contiguous values to determine if a freeflow condition exists.

In some embodiments, a predetermined range of contiguous values above athreshold (e.g., min and max ranges) of the summed rows of intensityvalues or intensity squared values may be used by the processor 90 todetermine if a drop of liquid is within the image. For example, each rowof the rows of the intensity values (or the intensity squared values)may be summed together and a range of the summed values may be above athreshold number; if the range of contiguous values is between a minimumrange and a maximum range, the processor 90 may determine that the rangeof contiguous values above a predetermined threshold is from a dropwithin the field of view of the image sensor 63 (see FIG. 8). In someembodiments of the present disclosure, the summed rows of intensityvalues or intensity squared values may be normalized, e.g., normalizedto have a value between 0 and 1.

The following describes a smoothing function similar to the cubic spline(i.e., the cubic-spline-type function) that may be used on the summedrows, the summed rows of intensity values, or the summed rows of theintensity values squared prior to the determination by the processor 90to determine if a free flow condition exits. In some specificembodiments, the cubic-spline-type function may be used to identifyblocks, as described infra, which may facilitate the processor's 90identification of free flow conditions.

The cubic-spline-type function is an analog to the cubic spline, but itsmoothes a data set rather than faithfully mimics a given function.Having data sampled on the interval from [0,1] (e.g., the summationalong a row of intensity squared or intensity that is normalized) theprocessor 90 (see FIG. 6 or 8) may find the best fit set of cubicfunctions on the intervals [x₀,x₁], [x₁,x₂], . . . , [x_(N−1),x_(N)]with x₀=0 and x_(N)=1 where the total function is continuous withcontinuous derivatives and continuous curvature.

The standard cubic spline definition is illustrated in Equation (1) asfollows:χ(x)=A _(i)(x)y _(i) +B _(i)(x)y _(i+1) +C _(i)(x)y″ _(i) +D _(i)(x)y″_(i+1) x _(i) ≦x≦x _(i+1)  (1),

with the functions A_(i), B_(i), C_(i), D_(i) defined as in the set ofEquations (2):

$\begin{matrix}{{{{A_{i}(x)} = {\frac{x_{i + 1} - x}{x_{i + 1} - x_{i}} = \frac{x_{i + 1} - x}{\Delta_{i}}}},{{B_{i}(x)} = {\frac{x - x_{i}}{x_{i + 1} - x_{i}} = \frac{x - x_{i}}{\Delta_{i}}}}}{{{C_{i}(x)} = {\frac{\Delta_{i}^{2}}{6}\left( {{A_{i}^{3}(x)} - {A_{i}(x)}} \right)}},{D_{i} = {\frac{\Delta_{i}^{2}}{6}{\left( {{B_{i}^{3}(x)} - {B_{i}(x)}} \right).}}}}} & (2)\end{matrix}$

The Equations (1) and (2) guaranty continuity and curvature continuity.The only values which can be freely chosen are y_(i), y″₀ and y″_(N).Please note that Equation (3) is chosen as follows:y″ ₀ =y″ ₁=0  (3),

i.e., the function is flat at 0 and 1. The remaining y″_(i) must satisfythe following set of Equations (4):

$\begin{matrix}{\mspace{70mu}{{{{\frac{y_{1} - y_{0}}{\Delta_{0}} + \frac{y_{1}^{''}\Delta_{0}}{3}} = {\frac{y_{2} - y_{1}}{\Delta_{1}} - \frac{y_{1}^{''}\Delta_{1}}{3} - \frac{y_{2}^{''}\Delta_{1}}{6}}}\mspace{70mu}{{\frac{y_{2} - y_{1}}{\Delta_{1}} + \frac{y_{1}^{''}\Delta_{1}}{6} + \frac{y_{2}^{''}\Delta_{1}}{3}} = {\frac{y_{3} - y_{2}}{\Delta_{2}} - \frac{y_{2}^{''}\Delta_{2}}{3} - \frac{y_{3}^{''}\Delta_{2}}{6}}}\mspace{65mu}{{\frac{y_{3} - y_{2}}{\Delta_{2}} + \frac{y_{2}^{''}\Delta_{2}}{6} + \frac{y_{3}^{''}\Delta_{2}}{3}} = {\frac{y_{4} - y_{3}}{\Delta_{3}} - \frac{y_{3}^{''}\Delta_{3}}{3} - \frac{y_{4}^{''}\Delta_{3}}{6}}}\mspace{70mu}\vdots{{\frac{y_{N - 2} - y_{N - 3}}{\Delta_{N - 3}} + \frac{y_{N - 3}^{''}\Delta_{N - 3}}{6} + \frac{y_{N - 2}^{''}\Delta_{N - 3}}{3}} = {\frac{y_{N - 1} - y_{N - 2}}{\Delta_{N - 2}} - \frac{y_{N - 2}^{''}\Delta_{N - 2}}{3} - \frac{y_{N - 1}^{''}\Delta_{N - 2}}{6}}}}\mspace{14mu}{{\frac{y_{N - 1} - y_{N - 2}}{\Delta_{N - 2}} + \frac{y_{N - 2}^{''}\Delta_{N - 2}}{6} + \frac{y_{N - 1}^{''}\Delta_{N - 2}}{3}} = {\frac{y_{N} - y_{N - 1}}{\Delta_{N - 1}} - {\frac{y_{N - 1}^{''}\Delta_{N - 1}}{3}.}}}}} & (4)\end{matrix}$

The set of Equations (4) can be rewritten as the set of Equations (5) asfollows:

$\begin{matrix}{\mspace{59mu}{{{{\frac{\Delta_{0} + \Delta_{1}}{3}y_{1}^{''}} + {\frac{\Delta_{1}}{6}y_{2}^{''}}} = {\frac{y_{0}}{\Delta_{0}} - {\left\lbrack {\frac{1}{\Delta_{0}} + \frac{1}{\Delta_{1}}} \right\rbrack y_{1}} + \frac{y_{2}}{\Delta_{1}}}}\mspace{56mu}{{{\frac{\Delta_{1}}{6}y_{1}^{''}} + {\frac{\Delta_{1} + \Delta_{2}}{3}y_{2}^{''}} + {\frac{\Delta_{2}}{6}y_{3}^{''}}} = {\frac{y_{1}}{\Delta_{1}} - {\left\lbrack {\frac{1}{\Delta_{1}} + \frac{1}{\Delta_{2}}} \right\rbrack y_{2}} + \frac{y_{3}}{\Delta_{2}}}}\mspace{50mu}{{{\frac{\Delta_{2}}{6}y_{2}^{''}} + {\frac{\Delta_{2} + \Delta_{3}}{3}y_{3}^{''}} + {\frac{\Delta_{3}}{6}y_{4}^{''}}} = {\frac{y_{2}}{\Delta_{2}} - {\left\lbrack {\frac{1}{\Delta_{2}} + \frac{1}{\Delta_{3}}} \right\rbrack y_{3}} + \frac{y_{4}}{\Delta_{3}}}}\mspace{65mu}\vdots\mspace{76mu}{{{\frac{\Delta_{N - 4}}{6}y_{N - 3}^{''}} + {\frac{\Delta_{N - 3} + \Delta_{N - 2}}{3}y_{N - 2}^{''}} + {\frac{\Delta_{N - 2}}{6}y_{N - 1}^{''}}} = {\frac{y_{N - 3}}{\Delta_{N - 3}} - {\left\lbrack {\frac{1}{\Delta_{N - 3}} + \frac{1}{\Delta_{N - 2}}} \right\rbrack y_{N - 2}} + \frac{y_{N - 1}}{\Delta_{N - 2}}}}{{{\frac{\Delta_{N - 1}}{6}y_{N - 2}^{''}} + {\frac{\Delta_{N - 2} + \Delta_{N - 1}}{3}y_{N - 1}^{''}}} = {\frac{y_{N - 2}}{\Delta_{N - 2}} - {\left\lbrack {\frac{1}{\Delta_{N - 2}} + \frac{1}{\Delta_{N - 1}}} \right\rbrack y_{N - 1}} + {\frac{y_{N}}{\Delta_{N - 1}}.}}}}} & (5)\end{matrix}$

In turn, this becomes the matrix Equation (6):

$\begin{matrix}{{\begin{bmatrix}\frac{\Delta_{0} + \Delta_{1}}{3} & \frac{\Delta_{1}}{6} & 0 & \; & 0 & 0 & 0 \\\frac{\Delta_{1}}{6} & \frac{\Delta_{1} + \Delta_{2}}{3} & \frac{\Delta_{2}}{6} & \ldots & 0 & 0 & 0 \\0 & \frac{\Delta_{2}}{6} & \frac{\Delta_{2} + \Delta_{3}}{3} & \; & 0 & 0 & 0 \\\; & \vdots & \; & \ddots & \; & \vdots & \; \\0 & 0 & 0 & \; & \frac{\begin{matrix}{\Delta_{N - 4} +} \\\Delta_{N - 3}\end{matrix}}{3} & \frac{\Delta_{N - 3}}{6} & 0 \\0 & 0 & 0 & \ldots & \frac{\Delta_{N - 3}}{6} & \frac{\begin{matrix}{\Delta_{N - 3} +} \\\Delta_{N - 2}\end{matrix}}{3} & \frac{\Delta_{N - 2}}{6} \\0 & 0 & 0 & \; & 0 & \frac{\Delta_{N - 2}}{6} & \frac{\begin{matrix}{\Delta_{N - 2} +} \\\Delta_{N - 1}\end{matrix}}{3}\end{bmatrix}\begin{Bmatrix}y_{1}^{''} \\y_{2}^{''} \\y_{3}^{''} \\\vdots \\y_{N - 3}^{''} \\y_{N - 2}^{''} \\y_{N - 1}^{''}\end{Bmatrix}} = {\quad{\left\lbrack \begin{matrix}\frac{1}{\Delta_{0}} & \begin{matrix}{{- \frac{1}{\Delta_{0}}} -} \\\frac{1}{\Delta_{1}}\end{matrix} & \frac{1}{\Delta_{1}} & \; & 0 & 0 & 0 \\0 & \frac{1}{\Delta_{1}} & \begin{matrix}{{- \frac{1}{\Delta_{1}}} -} \\\frac{1}{\Delta_{2}}\end{matrix} & \ldots & 0 & 0 & 0 \\0 & 0 & \frac{1}{\Delta_{2}} & \; & 0 & 0 & 0 \\\; & \vdots & \; & \ddots & \; & \vdots & \; \\0 & 0 & 0 & \; & \frac{1}{\Delta_{N - 3}} & 0 & 0 \\0 & 0 & 0 & \ldots & \begin{matrix}{{- \frac{1}{\Delta_{N - 3}}} -} \\\frac{1}{\Delta_{N - 2}}\end{matrix} & \frac{1}{\Delta_{N - 2}} & 0 \\0 & 0 & 0 & \; & \frac{1}{\Delta_{N - 2}} & \begin{matrix}{{- \frac{1}{\Delta_{N - 2}}} -} \\\frac{1}{\Delta_{N - 1}}\end{matrix} & \frac{1}{\Delta_{N - 1}}\end{matrix} \right\rbrack\;\begin{Bmatrix}y_{0} \\y_{1} \\y_{2} \\y_{3} \\\vdots \\y_{N - 3} \\y_{N - 2} \\y_{N - 1} \\y_{N}\end{Bmatrix}}}} & (6)\end{matrix}$

The matrix Equation (6) may be rewritten as the set of Equations (7) asfollows:Fy _(dd) =Gyy _(dd) =F ⁻¹ Gy=Hy  (7).

Choosing the values in the vector y using a least squares criterion onthe collected data is shown in Equation (8) as follows:E=Σ[ψ _(k) =A _(i) _(k) (ξ_(k))y _(i) _(k) −B _(i) _(k) (ξ_(k))y _(i)_(k) ₊₁ −C _(i) _(k) (ξ_(k))y″ _(i) _(k) −D _(i) _(k) (ξ_(k))y″ _(i)_(k) ]²   (8).

Equation (8) is the minimum deviation between the data and the spline,i.e., Equation (8) is an error function. The y values are chosen tominimize the error as defined in Equation (8). The vector of predictedvalues can be written as illustrated in Equation (9) as follows:

$\begin{matrix}\begin{matrix}{\hat{y} = {{\left( {A_{\{ k\}} + B_{\{ k\}}} \right)y} + {\left( {C_{\{ k\}} + D_{\{ k\}}} \right)y_{dd}}}} \\{= {{\left( {A_{\{ k\}} + B_{\{ k\}}} \right)y} + {\left( {C_{\{ k\}} + D_{\{ k\}}} \right){Hy}}}} \\{= {\left\lbrack {A_{\{ k\}} + B_{\{ k\}} + {C_{\{ k\}}H} + {D_{\{ k\}}H}} \right\rbrack y}} \\{= {{Ay}.}}\end{matrix} & (9)\end{matrix}$

The elements of the matrix in brackets of Equation (9) depend upon thex-value corresponding to each data point (but this is a fixed matrix).Thus, the final equation can be determined using the pseudo-inverse. Inturn, the pseudo-inverse only depends upon the x-locations of the dataset and the locations where the breaks in the cubic spline are set. Theimplication of this is that once the geometry of the spline and the sizeof the image are selected, the best choice for y given a set of measuredvalues y_(m) is illustrated in Equation (10) as follows:y=(A ^(T) A)⁻¹ A·y _(m)  (10).

The cubic spline through the sum intensity-squared function of the imagewill then be given by Equation (11) as follows:y _(cs) =A·y  (11).

Because the maximum values of the cubic spline are of interest, thederivative of the cubic spline is determined and utilized to determinethe maximum values of the cubic spline. The cubic spline derivative isgiven by Equation (12) as follows:

$\begin{matrix}\begin{matrix}{{\chi^{\prime}\left( x_{k} \right)} = {{{A_{i_{k}}^{\prime}\left( x_{k} \right)}y_{i_{k}}} + {{B_{i_{k}}^{\prime}\left( x_{k} \right)}y_{i_{k} + 1}} + {{C_{i_{k}}^{\prime}\left( x_{k} \right)}y_{i_{k}}^{''}} + {{D_{i_{k}}^{\prime}\left( x_{k} \right)}y_{i_{k} + 1}^{''}}}} \\{= {{- \frac{y_{i_{k}}}{\Delta_{i_{k}}}} + \frac{y_{i_{k} + 1}}{\Delta_{i_{k}}} - {\frac{\Delta_{i_{k}}y_{i_{k}}^{''}}{6}\left( {{3\;{A_{i_{k}}^{2}\left( x_{k} \right)}} - 1} \right)} +}} \\{\frac{\Delta_{i_{k}}y_{i_{k} + 1}^{''}}{6}{\left( {{3\;{B_{i_{k}}^{2}\left( x_{k} \right)}} - 1} \right).}}\end{matrix} & (12)\end{matrix}$

Equation (12) can be written as Equation (13) as follows:

$\begin{matrix}\begin{matrix}{y_{cs}^{\prime} = {{\left( {A_{\{ k\}}^{\prime} + B_{\{ k\}}^{\prime}} \right)y} + {\left( {C_{\{ k\}}^{\prime} + D_{\{ k\}}^{\prime}} \right)y_{dd}}}} \\{= {\left\lbrack {A_{\{ k\}}^{\prime} + B_{\{ k\}}^{\prime} + {C_{\{ k\}}^{\prime}H} + {D_{\{ k\}}^{\prime}H}} \right\rbrack y}} \\{= {A^{\prime}{y.}}}\end{matrix} & (13)\end{matrix}$

Once the current values of y are found, the cubic spline, y_(cs), andits derivative, y′_(cs), can be calculated. The cubic spline data mayinclude “blocks” of data that includes values above a predeterminedthreshold. A pipe block is formed by the liquid flowing out of the tubeinto the drip chamber 59 and a pool block is formed as the liquidcollects at the gravity end of the drip chamber 59 (see FIG. 8).

The following algorithm may be applied to the cubic spline data: (1)determine the local maxima of the cubic spline data using the derivativeinformation; (2) determine the block surrounding each local maxima byincluding all points where the cubic spline value is above a thresholdvalue; (3) merge all blocks which intersect; (4) calculate informationabout the block of data including the center of mass (intensity), thesecond moment of the mass (intensity), the lower x-value of the block,the upper x-value of the block, the mean value of the original sum ofintensity squared data in the block, the standard deviation of theoriginal sum of intensity squared data in the block, and the meanintensity of a high-pass filtered image set in the block; and (5)interpret the collected data to obtain information about when dropsoccur and when the system is streaming.

The mean intensity of a high-pass filtered image set in the block isused to determine if the block created by each contiguous range ofspline data is a result of a high frequency artifact (e.g., a drop) or alow frequency artifact. This will act as a second background filterwhich tends to remove artifacts such as condensation from the image.That is, all previous images in an image memory buffer (e.g., 30previous frames, for example) are used to determine if the data is aresult of high frequency movement between frames. If the block is aresult of low frequency changes, the block is removed, or if it is aresult of high frequency changes, the block is kept for furtheranalysis. A finite impulse response filter or an infinite impulseresponse filter may be used.

Each block is plotted over its physical extent with the height equal tothe mean value of the data within the block. If a block has a mean valueof the high-pass filtered image less than the threshold, it is anindication that it has been around for several images and thus may beremoved.

Free flow conditions may be determined by the processor 90 (see FIG. 6or 8) to exist using the blocks when the pipe block extends nearly tothe pool block, the pipe block and the pool block merge together, and/orthe summed range of widths of the pool and pipe blocks (or all blocks)is greater than a predetermined threshold, e.g., the total extent of theblocks exceeds 380 pixels in width. The processor 90 may detect a dropwhen the transition of the pipe block from a larger width to a shorterwidth occurs as a result of a drop formation in the tube and as the dropleaves the pipe (i.e., tube) opening of the drip chamber 59. Theprocessor 90 may detect this by looking at the ratio of the current pipeblock width to the previous image's pipe block width, e.g., an imagewhere the ratio is less than 0.9 as is also a local minima may beconsidered by the processor 90 to be an image formed immediately after adrop has formed.

Various filtering algorithms may be used to detect condensation or otherlow frequency artifacts, such as: if a block has a low mean value in thehigh-pass filtered image, then it may be condensation. This artifact canbe removed from consideration. Additionally or alternatively, longblocks (e.g., greater than a predetermined threshold) with a lowhigh-pass mean value are possibly streams because stream images tend toremain unchanging; the processor 90 may determine that long blocksgreater than a predetermined threshold corresponds to a streamingcondition. Additionally or alternatively, an algorithm may be used onthe current image to detect free flow conditions.

The processor 90 may, in some specific embodiments, use the block datato count the drops to use the system 84 as a drop counter. The processor90 may also use width changes in the pool block as a drop disturbs thewater to determine if a bubble formed when the drop hits the pool. Forexample, the processor 90 may determine that blocks that form below thepool block are from bubbles that formed when the drop hit the water. Thebubble may be filtered out by the processor 90 when determining if apredetermined value of total block ranges indicates that a free flowcondition exists.

In some embodiments of the present disclosure, the depth of field of thesystem 84 may have a narrow depth of field to make the system 84 lesssensitive to condensation and droplets on the chamber walls. In someembodiments, a near focus system may be used.

Referring now to FIG. 19, in another embodiment of the presentdisclosure, a template 189 is used to determine if a free flow conditionexists. The template 189 is used by the processor 90 of FIG. 8 todetermine a pattern match score 190 when performing a template matchalgorithm on an image, e.g., the image 94 of FIG. 13. For example, thetemplate 189 may be compared to the image 94 to determine if a portionor all of the image 94 closely matches the template 189. As previouslymentioned, the image 94 of FIG. 13 is a difference between a backgroundimage and an image captured by the image sensor 63 of FIG. 8 that haseach pixel converted to either a black pixel if the difference value forthat pixel is below a threshold value or a white pixel if the differencevalue for that pixel is above a threshold value. All pixels of the image94 will be either a white pixel or a black pixel. If the pattern matchscore 190 is above a predetermined threshold, a free flow condition isdetermined to exist. The template matching method may utilize a templatematching algorithm as found in the Open Source Computer Vision(“OpenCV”) library. For example, the template 189 may be used with thematchTemplate( ) function call of the OpenCV library using theCV_TM_CCOEFF method or the method of CV_TM_CCOEFF_NORMED. TheCV_TM_CCOEFF method uses the pattern matching algorithm illustrated inEquation (14) as follows:

$\begin{matrix}{\mspace{79mu}{{{{R\left( {x,y} \right)} = {\sum\limits_{x^{\prime},y^{\prime}}^{\;}\;\left( {{T^{\prime}\left( {x^{\prime},y^{\prime}} \right)} \cdot {I^{\prime}\left( {{x + x^{\prime}},{y + y^{\prime}}} \right)}} \right)}},\mspace{79mu}{{where}\text{:}}}\mspace{79mu}{{T^{\prime}\left( {x^{\prime},y^{\prime}} \right)} = {{T\left( {x^{\prime},y^{\prime}} \right)} - {1\text{/}{\left( {w \cdot h} \right) \cdot {\sum\limits_{x^{''},y^{''}}^{\;}{T\left( {x^{''},y^{''}} \right)}}}}}}{{{I^{\prime}\left( {{x + x^{\prime}},{y + y^{\prime}}} \right)} = {{I\left( {{x + x^{\prime}},{y + y^{\prime}}} \right)} - {1\text{/}{\left( {w \cdot h} \right) \cdot {\sum\limits_{x^{''},y^{''}}^{\;}{I\left( {{x + x^{''}},{y + y^{''}}} \right)}}}}}};}}} & {(14),}\end{matrix}$The I denotes the image, the T denotes the template, and the R denotesthe results. The summation is done over the template and/or the imagepatch, such that: x′=0 . . . w−1 and y′=0 . . . h−1.

The results R can be used to determine how much the template T ismatched at a particular location within the image I as determined by thealgorithm. The OpenCV template match method of CV_TM_CCOEFF_NORMED usesthe pattern matching algorithm illustrated in Equation (15) as follows:

$\begin{matrix}{{R\left( {x,y} \right)} = {\frac{\sum\limits_{x^{\prime},y^{\prime}}^{\;}\;\left( {{T^{\prime}\left( {x^{\prime},y^{\prime}} \right)} \cdot {I^{\prime}\left( {{x + x^{\prime}},{y + y^{\prime}}} \right)}} \right)}{\sqrt{\sum\limits_{x^{\prime},y^{\prime}}^{\;}\;{{T^{\prime}\left( {x^{\prime},y^{\prime}} \right)}^{2} \cdot {\sum\limits_{x^{\prime},y^{\prime}}^{\;}{I^{\prime}\left( {{x + x^{\prime}},{y + y^{\prime}}} \right)}^{2}}}}}.}} & (16)\end{matrix}$

In another embodiment of the present disclosure, the template matchingalgorithm uses a Fast Fourier Transform (“FFT”). In some embodiments,any of the methods of the matchTemplate( ) function of OpenCV may beused, e.g., CV_TM_SQDIFF, CV_TM_SQDIFF_NORMED, CV_TM_CCORR, and/orCV_TM_CCORR_NORMED.

The CV_TM_SQDIFF uses the pattern matching algorithm illustrated inEquation (17) as follows:

$\begin{matrix}{{R\left( {x,y} \right)} = {\sum\limits_{x^{\prime},y^{\prime}}^{\;}\;{\left( {{T\left( {x^{\prime},y^{\prime}} \right)} - {I\left( {{x + x^{\prime}},{y + y^{\prime}}} \right)}} \right)^{2}.}}} & (17)\end{matrix}$

CV_TM_SQDIFF_NORMED uses the pattern matching algorithm illustrated inEquation (18) as follows:

$\begin{matrix}{{R\left( {x,y} \right)} = {\frac{\sum\limits_{x^{\prime},y^{\prime}}^{\;}\;\left( {{T\left( {x^{\prime},y^{\prime}} \right)} - {I\left( {{x + x^{\prime}},{y + y^{\prime}}} \right)}} \right)^{2}}{\sqrt{\sum\limits_{x^{\prime},y^{\prime}}^{\;}\;{{T\left( {x^{\prime},y^{\prime}} \right)}^{2} \cdot {\sum\limits_{x^{\prime},y^{\prime}}^{\;}{I\left( {{x + x^{\prime}},{y + y^{\prime}}} \right)}^{2}}}}}.}} & (18)\end{matrix}$

CV_TM_CCORR uses the pattern matching algorithm illustrated in Equation(19) as follows:

$\begin{matrix}{{R\left( {x,y} \right)} = {\sum\limits_{x^{\prime},y^{\prime}}^{\;}\;{\left( {{T\left( {x^{\prime},y^{\prime}} \right)} \cdot {I\left( {{x + x^{\prime}},{y + y^{\prime}}} \right)}} \right).}}} & (19)\end{matrix}$

CV_TM_CCORR_NORMED uses the pattern matching algorithm illustrated inEquation (20) as follows:

$\begin{matrix}{{R\left( {x,y} \right)} = {\frac{\sum\limits_{x^{\prime},y^{\prime}}^{\;}\;\left( {{T\left( {x^{\prime},y^{\prime}} \right)} \cdot {I^{\prime}\left( {{x + x^{\prime}},{y + y^{\prime}}} \right)}} \right)}{\sqrt{\sum\limits_{x^{\prime},y^{\prime}}^{\;}\;{{T\left( {x^{\prime},y^{\prime}} \right)}^{2} \cdot {\sum\limits_{x^{\prime},y^{\prime}}^{\;}{I\left( {{x + x^{\prime}},{y + y^{\prime}}} \right)}^{2}}}}}.}} & (20)\end{matrix}$

In yet another embodiment of the present disclosure, a template of agrayscale image of a free flow condition is compared to an image takenby the image sensor 63 of FIG. 8 to determine if a free flow conditionexists. In some embodiments, the template matching function within theOpenCV library may be utilized.

Refer now to FIGS. 20 and 21; in yet an additional embodiment of thepresent disclosure, the algorithm to determine when a free flowcondition exists, e.g., as executed by the processor 90 of FIG. 8, mayutilize an algorithm to determine if a template pattern matches an arrayof pixels utilizing edge detection followed by line detection. As shownin FIG. 20, an image 98 is formed from an image 99 of FIG. 21, by usingedge detected followed by line detection. The resulting lines may beutilized by the processor 90 to determine that a free flow conditionexists. As shown in FIG. 20, the feature which shows up after thisprocessing by the processor 90 are lines that have a different slopethan the expected 45° slope of the background reference image. The lineshaving the angle of the background image may be filtered out of FIG. 20,in some embodiments. The lines may be detected as edges using a Cannyalgorithm as found in the OpenCV library. The Hough algorithm also foundin the OpenCV library may be used to determine the slope of the lines.

One type of Hough transfer uses an algorithm described in ProgressiveProbabilistic Hough Transform by J. Matas, C. Galambos, and J. Kittlerin 1998 (“Algorithm 1”). However, the following “Alternative Hough”transform may be utilized and is shown in pseudo code form in Table 1(“Algorithm 2”). Algorithm 2 selects two pixels at random and calculatesthe Hough transform of the line passing through these two points.Algorithm 2 is shown in Table 1 as follows:

TABLE 1 Alternative Hough Transform Pseudocode 1.   If the image isempty, then exit. 2.   Randomly select two pixels and update theaccumulator   a. Required Operations      i. Two random numbers     ii.One inverse tangent 3.   Check if the new location is higher than thethreshold l. If not,    goto 1   a. Operations      i. One logicaloperation 4.   Look along a corridor specified by the peak in theaccumulator, and find the longest segment of pixels either continuous orexhibiting a gap not exceeding a given threshold. 5.   Remove the pixelsin the segment from the input image. 6.   Unvote from the accumulatorall the pixels from the line that have previously voted. 7.   If theline segment is longer than the minimum length add it to the output list8.   Goto 1.

If the line comprises a proportion, p, of the total points, then thelikelihood that we will see a result in the representative (r,θ)-bin isp for Algorithm 1 and p² for Algorithm 2. Generally, in someembodiments, a proportion test has at least 5 positive results and 5negative results. Assuming that it is more likely to see negativeresults than positive results, in some embodiments, the Algorithms 1 and2 continue to search for lines until there are at least 5 positiveresults in a particular bin.

The probability of seeing a fifth positive result in Algorithm 1 afterN≧5 tests is shown in Equation (21) as follows:

$\begin{matrix}{{{p_{1}\left( {5\mspace{14mu}{on}\mspace{14mu} N} \right)} = {{{p\left( {{4\mspace{14mu}{in}\mspace{14mu} N} - 1} \right)} \cdot p} = {\frac{\left( {N - 1} \right)!}{{4!}{\left( {N - 5} \right)!}}{p^{5}\left( {1 - p} \right)}^{N - 5}}}},} & (21)\end{matrix}$

and the probability in Algorithm 2 is shown in Equation (22) as follows:

$\begin{matrix}{{p_{2}\left( {5\mspace{14mu}{on}\mspace{14mu} N} \right)} = {{{p\left( {{4\mspace{14mu}{in}\mspace{14mu} N} - 1} \right)} \cdot p^{2}} = {\frac{\left( {N - 1} \right)!}{{4!}{\left( {N - 5} \right)!}}{{p^{10}\left( {1 - p^{2}} \right)}^{N - 5}.}}}} & (22)\end{matrix}$

Table 2, shown below, shows the number of tries to have a 50% chance ofseeing 5 successes, p_(1,50) and p_(2,50), as well as the number oftries to have a 90% chance of seeing 5 successes, p_(1,90) and p_(2,90).

TABLE 2 p p_(1,50) p_(1,90) p_(2,50) p_(2,90) r₅₀ r₉₀ 0.5 9 14 20 312.22 2.21 0.25 19 30 76 127 4 4.23 0.125 39 62 299 511 7.67 8.24 0.062576 127 1197 2046 15.75 16.11

Table 2 shows that the increase in the number of tries between Algorithm1 and Algorithm 2 to see 5 positive results is approximately 1/p. Thereshould be 1 positive result in 1/p trials when the proportion is p.

Algorithm 2's computationally expensive operation is, in someembodiments, the arc tangent function, which may be about 40 floatingpoint CPU operations. There are approximately 2N floating pointoperations in Algorithm 1's equivalent step. The Hough transform of a640×480 pixel image with full resolution has N equal to 2520, while theHough transform of a 1080×1920 pixel image has N equal to 7020. Thisimplies that Algorithm 2 has a speed advantage over Algorithm 1 when pis greater than 0.008 for a 640×480 image and when p is greater than0.003 for a 1080×1920 image.

In some embodiments, it is assumed that every bin in the Hough transformspace is equally likely to be occupied in the presence of noise. Thissimplification speeds up the thresholding decision; however, in someembodiments, this assumption is not true. The primary effect of thesimplification is to underestimate the probability that is seen invalues greater than one in the Hough transform with a correspondinglikelihood of falsely declaring that a line exists. For a particularcombination of image size and Hough transform bin arrangement, the trueprobabilities can be pre-computed. This allows the false alarm rate tobe minimized without a corresponding increase in computation. Withadditional restrictions on the type of imagery, even more accurateestimates of the probability of seeing a value in a bin of the Houghtransform is possible.

There are additional forms of the Hough transform which parameterizesdifferent features. For example, there is a three-elementparameterization of circles, (x,y,r), where x and y specify the centerand r is the radius. Algorithm 2 can work using these parameterizationsas well. For the circle example, Algorithm 2 would select three pixelsat random and calculate the circle passing through them.

Algorithm 2 would have a similar speed advantage for features comprisinga suitably large portion of the total pixels considered. It would alsohave a significant advantage in storage required, since the Houghtransform could be stored in a sparse matrix, while the Algorithm 1'sanalog would require a full-size matrix.

Referring now to FIGS. 22-26, which illustrate various backgroundpatterns that may be used to detect a free flow condition or estimatethe size of a drop of liquid. The image sensor 103 may be used with thebackground patterns of FIGS. 22-26 and may be the image sensor 11 ofFIG. 1, the image sensor 68 of FIG. 5, the image sensor 63 of FIG. 6, orthe image sensor 63 of FIG. 8, each of which may be coupled to arespective processor for processing the images from the image sensor,such as the processor 15 of FIG. 1 or the processor 90 of FIG. 8.

FIG. 22 is a block diagram of an imaging system 100 for use with thedrip chamber 104 (e.g., a drip chamber 4 of FIG. 1) having a backgroundpattern 101 with stripes and a light source 102 shining on the stripesfrom an adjacent location to an image sensor 103 in accordance with anembodiment of the present disclosure. Any drops or free flow streamswithin the drip chamber 104 distorts the image taken by the image sensor103. A processor coupled to the image sensor 103 (e.g., processor 15 ofFIG. 1) can use the distortions of the background pattern 101 ascaptured by the image sensor 103 to estimate a flow rate and/or detectfree flow conditions.

FIG. 23 is a block diagram of an imaging system 105 for use with thedrip chamber 104 having a background pattern 101 with stripes and alight source 102 shining on the stripes from behind the backgroundpattern 101 relative to an opposite end to an image sensor 103 inaccordance with an embodiment of the present disclosure. FIG. 24 showsan image from the image sensor 103 of FIG. 23 when a drop distorts thebackground pattern 101 of FIG. 23 in accordance with an embodiment ofthe present disclosure. Note that as shown in FIG. 24, the backgroundpattern's 101 stripes are distorted by the drop (or will be distorted bya free flow stream) in the drip chamber 104 as captured in images by theimage sensor 103. This distortion may be used to estimate the drop size,to calculate the flow rate through a drip chamber, or to determine if afree flow condition exists within the drip chamber.

FIG. 25 shows a block diagram of an imaging system 106 for use with aflow meter having a background pattern 107 with a checkerboard patternand a light source 102 shining on the stripes from behind the backgroundpattern 107 relative to an opposite end to an image sensor 103 inaccordance with an embodiment of the present disclosure. FIG. 26 showsan image from the image sensor 103 of FIG. 25 when a drop distorts thebackground pattern 107 of FIGS. 25-26 in accordance with an embodimentof the present disclosure. In yet another embodiment of the presentdisclosure, a background pattern having a plurality of random dotsand/or circles may be utilized by an imaging system disclosed herein.

Referring to FIGS. 22-26, the “lensing” of a drop (i.e., the distortionof the background pattern from the view of an image sensor) may be usedto measure the radius of the drop. The radius of the drop corresponds tohow much and what effect the drop has on any light passing through it.By measuring the change to the calibration grid (i.e., the backgroundpattern) as seen through the drop, the radius, and hence the volume ofthe drop, can be calculated. For example, the magnification of a testgrid of known size as seen through the drop could be measured opticallyand the radius inferred from this measurement. In some embodiments ofthe present disclosure, the relationship between the radius and the dropmay be calculated and/or may be determined using a lookup table that hasbeen generated empirically.

FIGS. 27-28 show a flow chart diagram illustrating a method forestimating a volume of a drop within a drip chamber in accordance withan embodiment of the present disclosure. That is, FIGS. 27-28 illustratea method 214. Method 214 will be also described with reference to FIGS.29-37. FIGS. 29-31 and 33-36 illustrate images used or generated by aflow meter to estimate a volume of a drop within a drip chamber inaccordance with an embodiment of the present disclosure. FIGS. 32 and 37illustrate pseudo code that may be used by the method 214 of FIGS.27-28.

The method 214 of FIGS. 27 and 28 may be implemented by the flow meter 7of FIG. 1, the flow meter 67 of FIG. 5, the imaging system 78 of FIG. 6,the imaging system 84 of FIG. 8, or other flow meter of an imagingsystem disclosed herein (each with or without a background patternand/or with or without active illumination).

The method 214 includes acts 200-213. Act 200 determines a baseline of adrop forming at an opening of a drip chamber. Act 201 captures a firstimage. The first image may be captured using a uniform backlight. Insome embodiments, the first image may be captured using a backgroundpattern and/or an exposure algorithm as described herein. Acts 200 and201 may be performed simultaneously. FIG. 29 shows an image with thebaseline 215 overlaid. The baseline 215 may be a predetermined group ofpixels or may be generated using fiducial markers disposed on theopening of the drip chamber and/or on a background pattern (not shown inFIG. 29). The first image is used by the method 214 to initialize abackground image, μ_(i,j), a variance array, s_(i,j), and an integerarray, I_(i,j). The background image may have i by j pixels, while thevariance array and the integer array may be 2-D arrays that also have asize of i by j.

Act 202 identifies the drop within the first image and a predeterminedband near an edge of the drop (e.g., the band may be a predeterminednumber of pixels beyond the edge of the drop). Act 203 initializes abackground image by setting each pixel to the same value as the firstimage (for that respective location) unless it is within the identifieddrop or a predetermined band near the edge of the drop. Act 204 setspixels within the region of the drop or within the predetermined band toa predetermined value. FIG. 30 shows an example background image createdafter initialization. In the exemplary image of FIG. 30, the area of thedrop and of a band beyond the edge of the drop, designated generally as216, is set to a predetermined value, e.g., 140.

For example, when the method creates the first background image, everypixel in the background image that is part of the drop or a band outsideof an edge of the drop is set to a default threshold value, e.g. 140 outof an intensity range of 0-255.

Act 205 initializes the integers of the array of integers to zeros. Act206 initializes the values within the array of variances to zeros. Theinteger array is the same size as the image. The integer array countshow often each pixel of the background image has been updated with newinformation and is initialized to all zeros. The array of variances(e.g., an array of the data type “double”) is also the same size as thebackground image and contains an estimate of the variance of theintensity of each pixel within the background image.

Act 207 captures another image, and act 208 identifies the drop in theanother image and another predetermined band near an edge of the drop.Act 209 updates the background image, the array of integers, and thearray of variances.

As additional images are captured, the background image may be updated.For example, when an image is collected by the system, the backgroundalgorithm evaluates every pixel. If a pixel is considered part of thedrop or its guard band, then its value in the background image is notaltered.

If a pixel is not considered part of the drop or its guard band: (1) ifthe pixel's corresponding integer in the integer array is zero, thepixel's value in the background image is set equal to the pixel's valuein the input image; or (2) if the pixel's count is greater than 0, thenthe background image value for that pixel is updated using a low passfilter. In some embodiments, any style of filter may be used, such as ahigh pass filter, a bandpass filter, etc. One low pass filter that maybe used is illustrated in Equation (23) as follows:P _(background,i,j) =P_(background,i,j)(1−α_(background))+α_(background) P _(input,i,j)  (23).

In addition, the variance array may be updated using Equations (24) asfollows:σ_(temp) ²=(P _(background,i,j) −P _(input,i,j))²σ_(background,i,j)=σ_(background,i,j)²(1−β_(background))+β_(background)σ_(temp) ²  (24).

Note that the filter used for both operations is an exponential filter;however, in additional embodiments, other suitable filters may be used,such as other low-pass filters. The variance estimate can be performedin any known way or using a stand in for the estimate, e.g., usingstandard deviation.

The new estimates of each pixel's background intensity (mean value), thenumber of images used to update each pixel's mean and variance, and eachpixel's variance (e.g., an approximation to the true variance and/or avalue that is proportional to the variance) are used to update thearrays. That is, each additional image captured may be used to updatethe background image, the array of integers, and the array of variances.After several images have been processed, the background image mayappear as FIG. 31. Note that this image still has a region (theuniformly medium gray area, designated generally as 217) where thepixels have never changed from the initial threshold value. This regionhas been considered part of the drop or its guard band in every image.

Act 210 compares the another image (e.g., current or most recent image)to the background image and identifies a plurality of pixels ofinterest. Act 211 determines a subset of pixels within the plurality ofpixels of interest that corresponds to a drop.

The comparison of act 210 compares the another image pixel-by-pixel tothe background image. Out of this comparison comes an array the samesize as the image where every pixel has a value of zero or not zero(255).

Act 210 may be implemented by the pseudo code shown in FIG. 32. That is,the determination of this threshold value is made in accordance with thefollowing: If the input pixel is to the left or right of the baseline inthe image, then its output value is set to zero (Line 1); if the inputpixel's background count array indicates that fewer than apre-determined number of images (e.g., 100) have been used to make thispixel's background value (Line 2), then: if the input pixel's intensityis less than the threshold intensity (e.g., 140 in a range of 0-255),then set the pixel's output value to not-zero (255) (Line 2 a); or ifthe input pixel's intensity is greater than or equal to the thresholdintensity, then set the pixel's output value to zero (Line 2 b); and ifthe input pixel's background count array is greater than thepre-determined number of images (Line 3), then: if the square of thedifference between the input pixel intensity and the background pixelintensity is greater than the pixel's estimate of background variancetimes a constant γ², then set the pixel's output value to not-zero (255)(Line 3 a) (that is, if the difference between current pixel value andthe background image is more than γ, then the pixel is distinct); or ifthe square of the difference between the input pixel intensity and thebackground pixel intensity is less than or equal to the pixel's estimateof background variance times a constant γ², then set the pixel's outputvalue to zero (see Line 3 b). Line 3 captures portions of the image thatare altered by the presence of a drop, but which are made a higherintensity.

When act 210 is implemented as an algorithm, the algorithm isinitialized, and the input and output of this thresholding algorithmwill look like the images in FIGS. 33 and 34, respectively. Because thenumber of images used in estimating the background image is initiallysmall, the only criterion applied are shown as lines (1) and (2) abovebecause there have not been enough images used for the integer array tohave a value beyond the threshold for certain respective pixels. Thismay result in many low-intensity regions being identified as distinct,including poorly illuminated edges and condensation on the chamberwalls.

After enough images have been gathered such that most (or all) of thepixels of the background image have been generated with a sufficientnumber of pixels, lines (3), (3 a), and (3 b) of FIG. 32 are utilized.After thresholding, the background is largely black with an occasionalnoisy pixel exceeding the variance threshold, as shown in FIGS. 35 and36 (which show an image captured by the camera and the results of thecomparison algorithm described above, respectively).

As previously mentioned, after act 210, act 211 determines which of asubset of pixels within the plurality of pixels of interest correspondsto a drop. Act 211 may be implemented by the pseudo code shown in FIG.37. That is, the threshold image is passed to an algorithm which findsthe connected component representing the drop as illustrated by thepseudo code of FIG. 37.

The binary image after processing the pseucode of FIG. 32 is evaluatedto find the binary component which occupies the space given by the drop.The algorithm is passed the location of a pixel on the baseline which iswhite (or it is passed the center pixel of the longest stretch ofcontiguous white pixels on the line).

Once the algorithm has an initial white pixel, it performs the algorithmillustrated by the pseudo code shown in FIG. 37. The pseudo codedetermines locations that include white pixels that have a path to thebaseline (i.e., a white pixel path). Line 1 pushes the location of thefirst pixel onto a stack. Line 2 performs a while loop while the stackis not empty. The while loop includes lines (2 a)-(2 d). Line 2 a popsthe next location (i,j) off of the stack. Line 2 b makes the outputpixel value at (i,j) white. Line 2 c examines the eight pixels adjacentto (i,j). Line (2 ci) is an “if statement,” and if the adjacent inputpixel (l,φ) is white, but the output pixel (l,φ) is black, line 2 c addsthe location (l,φ) to the stack. Line 2 d return to line 2 to continuethe while loop (if the stack remains empty).

This algorithm will set to white all output-pixel locations which can beconnected to the input pixel's location by a continuous path of whiteinput pixels. The left boundary of the drop is found by stepping througheach row of pixels from the left edge until the algorithm hits a whitepixel. The right boundary is found by stepping from the right edge ofthe image until it hits a white pixel. The first row where it ispossible to step from the left edge to the right edge without hitting awhite pixel is where the drop is considered to end.

The pseudo code shown in FIG. 37 is a one-pass version of aconnected-component labeling algorithm. However, otherconnected-component labeling algorithms or other suitable algorithms maybe used to determine which pixels correspond to the drop.

Act 212 of FIG. 28 performs a rotation operation on the subset ofpixels. Act 213 estimates a volume of the drop within the drip chamberby counting the number of pixels within the rotated subset of pixels.The total number of pixels within the 3-D version of the drop iscounted; and because each pixel corresponds to a distance, the number ofpixels may be used to estimate the volume of the drop.

Imaging System Optics

FIGS. 38-42 facilitate the following description of the optics of animaging system disclosed herein. For example, an image sensor disclosedherein may be an image sensor cube manufactured by OmniVision of 4275Burton Drive, Santa Clara, Calif. 95054; and, for example, the imagesensor cube may be one manufactured for phone image sensor applications.In some embodiments of the present disclosure, an image sensor disclosedherein may use a fixed focus and have a depth of field (“DOF”) from 15centimeters to infinity.

The image sensor may have the blur circle of a point imaged in the rangeof the image sensor entirely contained within the area of a singlepixel. The focal length of the image-sensor lens may be 1.15millimeters, the F# may be 3.0, and the aperture of the lens of theimage sensor may be 0.3833 millimeter. A first order approximation ofthe optical system of one or more of the image sensors may be made usingmatrix equations, where every ray, r, is represented as the vectordescribed in Equation (25) as follows:

$\begin{matrix}{r = {\left\{ \frac{h}{\theta} \right\}.}} & (25)\end{matrix}$

In Equation (25) above, h is the height of the ray at the entrance tothe image sensor, and θ is the angle of the ray. Referring to FIG. 38,when imaging a hypothetical point at a distance d_(im) from the lens ofone of the image sensors (which has focal length f) and the lens is adistance d_(fp) from the focal plane, the corresponding matrix, M_(cam),describing the image sensor is described by Equation (26) as follows:

$\begin{matrix}{M_{cam} = {\begin{bmatrix}1 & d_{fp} \\0 & 1\end{bmatrix} \cdot \begin{bmatrix}1 & 0 \\{- \frac{1}{f}} & 1\end{bmatrix} \cdot {\begin{bmatrix}1 & d_{im} \\0 & 1\end{bmatrix}.}}} & (26)\end{matrix}$

To find the place on the focal plane, fp, where the ray strikes, amatrix multiplication as described in Equation (27) as follows may beused:

$\begin{matrix}{\left\{ \frac{h_{fp}}{\theta_{fp}} \right\} = {M_{cam} \cdot {\left\{ \frac{h_{im}}{\theta_{im}} \right\}.}}} & (27)\end{matrix}$

As illustrated in FIG. 38, the diameter of the blur circle, D_(blur), isshown as approximately the distance between the two points illustratedin FIG. 38. This distance is found by tracing rays from the point,d_(im), away from the lens on the optical axis to the edges of the lensand then to the focal plane. These rays are given by the vectors shownin (28) as follows:

$\begin{matrix}{\begin{Bmatrix}0 \\\left( {{\pm \tan^{- 1}}\frac{D_{lens}}{2*d_{im}}} \right)\end{Bmatrix}.} & (28)\end{matrix}$

As shown in FIG. 39, the blur circle, D_(blur), is calculated and shownfor a variety of lens-to-focal plane separations and lens-to-imageseparations. A contour map 77 is also shown in FIG. 39. The x-axis showsthe distance in microns between the focal plane and a point located afocal length away from the lens of an image sensor. The y-axis shows thedistance in meters between the lens and the point being imaged. Thevalues creating the contour map 77 is the blur size divided by the pixelsize; therefore, anything about 1 or less is sufficient for imaging. Asshown in FIG. 39, the focal plane is located a focal length and anadditional 5 micrometers away from the lens.

The image sensor may utilize a second lens. For example, an image sensormay utilize a second lens to create a relatively larger depth of fieldand a relatively larger field of view. The depth of field utilizing twolenses can be calculated using the same analysis as above, but with theoptical matrix modified to accommodate for the second lens and theadditional distances, which is shown in Equation (29) as follows:

$\begin{matrix}{M_{sys} = {\begin{bmatrix}1 & d_{fp} \\0 & 1\end{bmatrix} \cdot \begin{bmatrix}1 & 0 \\{- \frac{1}{f_{cam}}} & 1\end{bmatrix} \cdot \begin{bmatrix}1 & d_{lens} \\0 & 1\end{bmatrix} \cdot \begin{bmatrix}1 & 0 \\{- \frac{1}{f_{lens}}} & 1\end{bmatrix} \cdot {\begin{bmatrix}1 & d_{im} \\0 & 1\end{bmatrix}.}}} & (29)\end{matrix}$

FIGS. 40 and 41 illustrate the field changes with the separation betweenthe lens and the image sensor and the corresponding change in the focusof the image sensor. FIGS. 40 and 41 show the blur circle divided by thepixel size. FIG. 40 shows the blur circle divided by pixel size when a20 millimeter focal-length lens is used. FIG. 41 shows the blur circledivided by pixel size when a 40 millimeter focal length lens is used.The corresponding fields of view about the optical axis for the cornersof the two configurations of FIGS. 40 and 41 are shown in the table inFIG. 42.

As shown in FIG. 42, in some embodiments, the image sensor may utilize a40 mm to 60 mm focal-length lens; this configuration may include placingan image sensor about 2 inches from the focus. In other embodiments ofthe present disclosure, other configurations may be used including thosenot shown in FIG. 42.

For example, the following analysis shows how the depth of field can beset for an image sensor using a lens of focal length, f, a distance, z,from the focal plane, and a distance, d, from a point in space; a matrixof the system is shown in Equation (30) as follows:

$\begin{matrix}{M = {\begin{bmatrix}1 & z \\0 & 1\end{bmatrix} \cdot \begin{bmatrix}1 & 0 \\{- \frac{1}{f}} & 1\end{bmatrix} \cdot {\begin{bmatrix}1 & d \\0 & 1\end{bmatrix}.}}} & (30)\end{matrix}$

Equation (30) reduces to Equation (31) as follows:

$\begin{matrix}{M = {\begin{bmatrix}1 & z \\0 & 1\end{bmatrix} \cdot {\begin{bmatrix}1 & d \\{- \frac{1}{f}} & {1 - \frac{d}{f}}\end{bmatrix}.}}} & (31)\end{matrix}$

Equation (31) reduces to Equation (32) as follows:

$\begin{matrix}{M = {\begin{bmatrix}{1 - \frac{z}{f}} & {d + z - \frac{dz}{f}} \\{- \frac{1}{f}} & {1 - \frac{d}{f}}\end{bmatrix}.}} & (32)\end{matrix}$

Considering the on-axis points, all of the heights will be zero. Thepoint on the focal plane where different rays will strike is given byEquation (33) as follows:

$\begin{matrix}{\left( {d + z - \frac{dz}{f}} \right){\theta.}} & (33)\end{matrix}$

As shown above in (33), θ is the angle of the ray. The point in perfectfocus is given by the lens maker's equation given in Equation (34) asfollows:

$\begin{matrix}{\frac{1}{f} = {\frac{1}{z} + {\frac{1}{d}.}}} & (34)\end{matrix}$

Equation (34) may be rearranged to derive Equation (35) as follows:

$\begin{matrix}{d = {\frac{1}{\frac{1}{f} - \frac{1}{z}} = {\frac{fz}{z - f}.}}} & (35)\end{matrix}$

Inserting d from Equation (35) into Equation (33) to show the strikingpoint results in Equation (36) as follows:

$\begin{matrix}{{\left\lbrack {\frac{fz}{z - f} + z - \frac{\frac{fz}{z - f}z}{f}} \right\rbrack\theta} = {{\frac{{f^{2}z} + {fz}^{2} - {f^{2}z} - {fz}^{2}}{f\left( {z - f} \right)}\theta} = 0.}} & (36)\end{matrix}$

All rays leaving this point strike the focal plane at the optical axis.As shown in Equation (37), the situation when the image sensor isshifted by a distance δ from the focus is described as follows:

$\begin{matrix}\begin{matrix}{{\left\lbrack {\frac{fz}{z - f} + \delta + z - \frac{\left\lbrack {\frac{fz}{z - f} + \delta} \right\rbrack z}{f}} \right\rbrack\theta} = {\frac{\begin{matrix}{{f^{2}z} + {{fz}\;\delta} - {f^{2}\delta} + {fz}^{2} -} \\{{f^{2}z} - {fz}^{2} - {\delta\; z^{2}} + {f\;\delta\; z}}\end{matrix}}{f\left( {z - f} \right)}\theta}} \\{= {\frac{{fz} - f^{2} - z^{2} + {fz}}{f\left( {z - f} \right)}\delta\;\theta}} \\{= {{- \frac{\left( {z - f} \right)^{2}}{f\left( {z - f} \right)}}\delta\;\theta}} \\{= {\frac{f - z}{f}\delta\;{\theta.}}}\end{matrix} & (37)\end{matrix}$

Equation (37) shows that by properly positioning the lens of the imagesensor with respect to the focal plane, we can change the depth offield. Additionally, the spot size depends upon the magnitude of theangle θ. This angle depends linearly on the aperture of the visionsystem created by the image sensor.

Additionally or alternatively, in accordance with some embodiments ofthe present disclosure, an image sensor may be implemented by adjustingfor various parameters, including: the distance to the focus as itaffects compactness, alignment, and sensitivity of the vision system tothe environment; the field of view of the system; and the lens-focalplane separation as it affects the tolerances on alignment of the systemand the sensitivity of the system to the environment.

Embodiments of the Flow Meter with or without Valves Connected Thereto

Referring to the drawings, FIGS. 43 and 44 show a flow meter 58 coupledto a drip chamber 59. As described infra, the flow meter 58 mayoptionally include a free flow detector component 12 (see FIG. 1) inaccordance with an embodiment of the present disclosure. Additionally,alternatively, or optionally, the flow meter 58 may include a flow rateestimator component 13 (see FIG. 1) in accordance with some embodimentsof the present disclosure. FIG. 43 shows the flow meter 58 with a shutdoor 62, and FIG. 44 shows the flow meter 58 with an open door 62. Theflow meter 58 may be the flow meter 7 of FIG. 1 with a valve 6 or withno valve. The flow meter 58 includes a start button 60 and a stop button61. Additionally or optionally, the flow meter 58 may include a backupvalve to stop fluid from flowing therethrough or may signal anothervalve to stop the fluid from flowing in response to error conditions.

The flow meter 58 optionally includes image sensors 63 and 64 that canestimate fluid flow and/or detect free flow conditions. Although theflow meter 58 includes two image sensors (e.g., 63 and 64), only one ofthe image sensors 63 and 64 may be used in some embodiments. The imagesensors 63 and 64 can image a drop while being formed within the dripchamber 59 and estimate its size. The size of the drop may be used toestimate fluid flow through the drip chamber 59. For example, in someembodiments of the present disclosure, the image sensors 63 and 64 usean edge detection algorithm to estimate the outline of the size of adrop formed within the drip chamber 59; a processor therein (seeprocessor 15 of FIG. 1, processor 75 of FIG. 5, or processor 90 of FIG.6 or 8) may assume the outline is uniform from every angle of the dropand can estimate the drop's size from the outline. In the exemplaryembodiment shown in FIGS. 43 and 44, the two image sensors 63 and 64 mayaverage together the two outlines to estimate the drop's size. Forexample, the algorithm may average the measured outlines of the twoimage sensor 63 and 64 to determine the size of the drop. The imagesensors 63 and 64 may use a reference background pattern to facilitatethe recognition of the size of the drop as described herein.

In another embodiment of the present disclosure, the image sensors 63and 64 image the fluid to determine if a free flow condition exists. Theimage sensors 63 and 64 may use a background pattern to determine if thefluid is freely flowing (i.e., drops are not forming and the fluidstreams through the drip chamber 59). As previously mentioned, althoughthe flow meter 58 includes two image sensors (e.g., 63 and 64), only oneof the image sensors 64 and 64 may be used in some embodiments todetermine if a free flow condition exists and/or to estimate the flow offluid through the drip chamber.

Additionally or alternatively, in some embodiments of the presentdisclosure, another image sensor 65 monitors the fluid tube 66 to detectthe presence of one or more bubbles within the fluid tube. Inalternative embodiments, other bubble detectors may be used in place ofthe image sensor 65. In yet additional embodiments, no bubble detectionis used in the flow meter 58.

Referring now to the drawings, FIG. 45 shows a flow meter 218 coupled toa drip chamber 219 in accordance with an embodiment of the presentdisclosure. The drip chamber 219 is secured to the flow meter 218 viacouplers 410. A backlight 220 shines light through the drip chambertoward the image sensor 221 (shown in outlined form).

The flow meter 218 may electronically transmit a flow rate to amonitoring client 8 (see FIG. 1). Additionally or alternatively, in someoptional embodiments, the flow meter 218 may include a display thatdisplays a flow rate (e.g., a touch screen, an LED display, and thelike). The flow meter 218 may be coupled to a pole 223 via clamps 222.

In some embodiments, the flow meter 218 may be coupled to an actuatorwhich is coupled to a valve (not shown in FIG. 45) to form a closed-loopsystem (e.g., the control component 14 of FIG. 1, such as a PID,bang-bang, neural network, or fuzzy logic control system) to regulatethe flow of fluid through the drip chamber 219.

The flow meter 218 may use any flow algorithm described herein and mayinclude any imaging system described herein. Additionally oralternatively, the flow meter 218 may include a free flow detectorcomponent (e.g., the free flow detector component 12 of FIG. 1).

FIG. 46 shows a flow meter 224 and a pinch valve 225 coupled to the body226 of the flow meter 224 to control the flow of fluid to a patient inaccordance with an embodiment of the present disclosure. The flow meter224 includes an image sensor 227 and a backlight 228.

The image sensor 227 images a drip chamber 229 and can receiveillumination from the backlight 228. The flow meter 224 includes asupport member 230 coupled to a coupler 231 that couples the dripchamber 229 to the flow meter 224.

The flow meter 224 may implement any flow rate estimator describedherein (e.g., the flow rate estimator component 13 of FIG. 1) and/or afree flow detector disclosed herein (e.g., the free flow detectorcomponent 12 of FIG. 1). The flow meter 224 may use the pinch valve 225in a close-loop fashion to control the flow of fluid to a patient (e.g.,using a control component 14 as shown in FIG. 1).

The pinch valve 225, as is more easily seen in FIG. 47, is coupled to ashaft 233 which is coupled to an actuator 234. The actuator 234 may be asolenoid or any actuator that can move the pinch valve 225 toward a tube335.

FIG. 48 shows a flow meter 336 and a pinch valve 225 in accordance withan embodiment of the present disclosure. The flow meter includes twoimage sensors 337 and 338. The flow meter 336 may use the pinch valve225 in a closed-loop feedback configuration. The flow meter 336 mayimplement a volume estimation algorithm described herein using bothimage sensors 337 and 338 to estimate the flow of fluid through the dripchamber 229. For example, the flow meter 336 may average the two volumestogether for use in the feedback loop.

FIG. 49 shows a flow meter 339 and a valve 340 coupled to an actuator341 to control the flow of fluid into a patient in accordance with anembodiment of the present disclosure. The flow meter 339 of FIG. 49 issimilar to the flow meter 224 of FIG. 46; however, the flow meter 339 ofFIG. 49 includes a valve 340 that has curved, elongated support members342 and 343 (see FIGS. 50A-50B).

The flow meter 339 includes an image sensor 227 and a backlight 228. Theimage sensor 227 images a drip chamber 229 and can receive illuminationfrom the backlight 228. The flow meter 339 includes a support member 230coupled to a coupler 231 that couples the drip chamber 229 to the flowmeter 339.

The flow meter 339 can implement any flow rate estimator describedherein (e.g., the flow rate estimator component 13 of FIG. 1) and/or afree flow detector disclosed herein (e.g., the free flow detectorcomponent 12 of FIG. 1). The flow meter 339 may use the valve 340 in aclose-loop fashion to control the flow of fluid into a patient (e.g.,using the control component 14 of FIG. 1).

The flow meter 339 may actuate the actuator 341 to actuate the valve340, which thereby regulates the fluid flowing through the IV tube 335in a feedback (i.e., closed-loop) configuration using any controlalgorithm.

Referring now to FIGS. 50A-50B, which shows close-up views of the valve340 of FIG. 49 in accordance with an embodiment of the presentdisclosure. The valve 340 includes an inner curved, elongated supportmember 343 and an outer curved, elongated support member 342. The tube335 is positioned between the support members 342 and 343.

The inner support member 343 includes a barrel nut 344. The outersupport member 342 is coupled to the barrel nut 344 via hooks 345. Insome embodiments, the barrel nut 344 is not coupled to the valve 340 andthe inner support member 342 includes a hole for the threaded rod orscrew 347 to slide through. The outer support member 342 also has hooks348 to secure it to a frame 349 of the actuator 341. The actuator 341includes a shaft 346 coupled to a screw 347. As the actuator 341 rotatesthe shaft 346, the screw 347 can rotate to push the barrel nut 334toward the actuator 341. That is, the hooks 345 and the barrel nut 334move toward the hooks 348 and the frame 349 because the inner and outersupport members 342 and 343 are flexible.

As the support members 342 and 343 are compressed, the tube 335 becomescompressed because it is positioned between the support members 342 and343. Compression of the tube 335 restricts the flow of fluid through thetube 335. The valve 340 compresses a length of the tube 335 that issubstantially greater than the diameter of the tube 335.

FIGS. 51A-51D show several views of a flow meter 350 with a monitoringclient 358, a valve 352, a drip chamber 357, an IV bag 411, and a fluidtube 412 in accordance with an embodiment of the present disclosure. Theflow meter 350 includes a receiving portion 351 to receive the valve352. The valve 352 includes two curved, elongated support members 353and 354.

The flow meter 350 includes an image sensor 355 and a backlight 356 thatcan monitor drops formed within the drip chamber 357. The flow meter 350may use the image sensor 355 to implement a flow rate estimatoralgorithm described herein (e.g., the flow rate estimator component 13of FIG. 1) and/or to implement a free flow detector disclosed herein(e.g., the free flow detector component 12 of FIG. 1).

The flow meter 350 includes a base 359 that can form a dock to receivethe monitoring client 358. The monitoring client 358 may be a smartphone, or other electronic computing device (e.g., an Android-baseddevice, an Iphone, a tablet, a PDA, and the like).

The monitoring client 358 may contain software therein to implement afree flow detector, a flow rate estimator, a control component, anexposure component, etc. (e.g., the free flow detector component 12, theflow rate estimator component 13, the control component 14, the exposurecomponent 29 of FIG. 1) and may contain one or more transceivers (e.g.,the transceiver 9). Additionally or alternatively, the base 359 of theflow meter 350 may implement these items.

For example, the flow meter 350 may implement a free flow detector, aflow rate estimator, a control component, an exposure component, etc.using internal software, hardware, electronics, and the like. The flowmeter 350 may implement a closed-loop feedback system to regulate thefluid flowing to a patient by varying the fluid flowing through thevalve 352.

As is easily seen in FIG. 51B, the valve 352 includes an inner supportmember 354 and an outer support member 353. The inner support member 354is coupled to a barrel nut 360 and to a barrel 361. In some embodiments,the barrel nut 360 is not coupled to the inner support member 354, andthe inner support member 354 includes a hole for the threaded shaft 362to slide through.

A threaded shaft 362 (e.g., a screw) spins freely within a bearinglocated within the barrel 361 and engages a threaded nut within thebarrel nut 360 to push or pull the barrel nut 360 relative to the barrel361 by rotation of the knob 363 (e.g., the actuator is a lead screwhaving a knob to actuate the lead screw). The knob 363 may be manuallyrotated.

Additionally or alternatively, the valve 352 may be snapped into thereceiving portion 351 which includes a rotating member 364 that engagesthe knob 363 within the receiving portion 351 (see FIG. 51C). Therotating member 364 engages the rotating knob 363 to actuate the valve352. The rotating member 364 may be coupled to an electric motor whichrotates the rotating member 364. The electric motor (not explicitlyshown) may be controlled by the flow meter 350 in a closed-loopconfiguration to achieve a target flow rate of fluid flowing into apatient.

FIGS. 52A-52D show several views of another flow meter 365 with a valve352, a drip chamber 357, and a fluid tube trench 413 having a receivingportion 351 to receive a valve 352 in accordance with an embodiment ofthe present disclosure. The flow meter 365 of FIGS. 52A-52D is similarto the flow meter 350 of FIGS. 51A-51D; however, the base 359 holds themonitoring client 358 in an “upright” position. Additionally, thereceiving portion 351 is on an opposite side of the base 359 from themonitoring client 358 (see FIGS. 52B and 52C).

FIG. 52D shows a close-up view of the valve 352 engaging the receivingportion 351. The knob 363 engages a rotating member that is internal tothe base 359 (not shown in FIG. 52D) that is coupled to a motor (alsonot shown in FIG. 52D).

FIG. 53A shows another view of the valve 352 of FIGS. 51A-51D and52A-52D, and FIGS. 53B-53C show two exploded views of the valve of FIG.53A in accordance with an embodiment of the present disclosure.

As shown in FIGS. 53A-53C, the valve 352 includes an inner supportmember 354 and outer support member 353. A tube may be inserted throughholes 366 and 367 to position the tube between the support members 354and 353.

The knob 363 may be turned to turn the screw 362. Rotation of the screw362 causes the barrel nut 360 to move toward the partial barrel 363 tocompress a tube positioned between the support members 353 and 354. Thepartial barrel 363 includes two sides, however, there is a space to holdthe end 600 (e.g., the cap) of the screw 362 securely within the space(e.g., a complementary space). FIG. 54 shows the valve 352 in manual useand coupled to a tube 368.

FIG. 55 shows a valve 369 that includes two flexible members 370 and 371in accordance with an embodiment of the present disclosure. The flexiblemembers 370 and 371 may be two flexible sheets. The flexible member 371may include holes 373 and 374 for a tube 372 to be positioned betweenthe flexible members 370 and 371.

The flexible members 370 and 371 are coupled together via two connectormembers 377 and 378. The connector members 377 and 378 are coupled tocoupling members 376 and 375, respectively.

Actuation of the valve 369 may be by a linear actuator that pulls thecoupling members 375, 376 toward each other or away from each other. Thelinear actuator (not explicitly shown) may be a screw-type actuator, apiston actuator, or other actuator. In some embodiments, one of thecoupling members 375 and 376 may be coupled to a stationary supportwhile the actuator is coupled to the other one of the coupling members375 and 376 and another stationary support for pulling the couplingmembers 375 and 376 together or apart.

FIGS. 56A-56C show several views of a valve 380 having two curved,elongated support members 381 and 382 with one of the elongated supportmembers 381 having a plurality of ridges 387 adapted to engage a tubepositioned between the support members 381 and 382, in accordance withan embodiment of the present disclosure.

The valve 380 has both support members 381 and 382 coupled to a couplingmember 383 at a first end and a second coupling member 384 at anotherend. That is, the coupling member 384 surrounds a screw 385, and thecoupling member 383 includes internal threads for pulling the couplingmember 383 toward or away from a knob 386 when the screw 385 is rotatedwith rotation of the knob 386. FIG. 56B shows the valve 380 whenactuated to close fluid flowing through a tube coupled between thesupport members 381 and 382. FIG. 56C shows the support member 381having two holes 388 and 389 to receive a tube. Also note that thesupport members 381 and 382 hold a tube off center from an axis of thescrew 385, which is easily seen in FIG. 56C. Holding the tube off-centerfrom the screw's 385 axis facilitates free movement of the tube.

FIGS. 57A-57C show several views of a valve 390 having a ratchet 394that engages a connecting member 393 of the valve 390 in accordance withan embodiment of the present disclosure, and FIGS. 57D-57E show twoexploded views of the valve 390 of FIGS. 57A-57C. The ratchet 394engages the connecting member 393 by interacting with a gear rack 397disposed thereon. A finger 602 (see FIGS. 57D and 57E) interacts with agear rack 397 to provide the ratcheting action. That is, the finger 602may hold the gear rack 397 against an engaging finger on a side oppositeof the retaining finger 602. The valve 390 includes a support member 391having an end coupled to the ratchet 394 and another end pivotallycoupled to a hinge 395. The valve 390 also includes a support member 392having hooks 398 that can couple to the body of the ratchet 394.

As shown in FIG. 57C, a tube 396 can be positioned between the supportmembers 391 and 392, the hooks 398 can then be fastened to the body ofthe ratchet 394, and the connecting member 393 can be inserted into theratchet 394 (as shown in FIG. 57B). As shown in FIG. 57C, the tube 396is positioned against the support member 391 via openings 399 and 400.

The ratchet 394 engages the gear rack 397 such that the ratchet 394 canbe manually moved toward the hinge 395 for course fluid flowadjustments. Thereafter, a knob (not shown) may be coupled to theratchet 394 to make fine adjustments to the distance between the ratchet394 and the hinge 395. Additionally or alternatively, the ratchet 394may include a release button (not shown) to release the ratchet from theconnecting member 393.

FIGS. 58A-58D show several views of a valve 401 having two elongatedsupport members 403 and 404, a connecting member 405, and a screw-typeactuator 407 in accordance with another embodiment of the presentdisclosure.

The support members 403 and 404 may be permanently molded together attheir ends with the ends of the connecting member 405. A tube 402 may bepositioned between the support members 403 and 404.

As the knob 408 is turned, the screw-type actuator 407 expands orcontracts because of engagement with a threaded rod 406. FIG. 58A showsthe valve in an open position while FIG. 58B shows the valve in a closedposition. Note that the tube 402 is squeezed along a substantial lengthof the tube 402. FIGS. 58C-58D show the valve 401 in the open positionand the closed position, respectively, from a perspective view.

FIGS. 59A-59C show several views of a body 501 of a valve 500 (see FIG.59H for the assembled valve 500) in accordance with an embodiment of thepresent disclosure. The body 501 includes a first curved, elongatedsupport member 502 and a second curved, elongated support member 503.The first support member 502 includes raised holes 504, 505 to hold atube between the support members 502 and 503.

The body 501 also includes a first connector 506 that is coupled to thesupport members 503, 504 at an end, and a second connector 507 that iscoupled to the other ends of the support members 503, 504.

The first connector 506 is coupled to an end of the support members 503,504 and to a first end 508 of a connecting member 509. The secondconnector 507 includes a hole 510 for positioning the second end 511 ofthe connector member 509 therethrough (as is easily seen in FIG. 59B).

When a tube is positioned between the support members 502, 503, movementof the second connector 507 toward the first connector 506 compressesthe tube disposed between the support members 502, 503. As the secondconnector 507 moves towards the first connector, the hole 510 of thesecond connector 507 allows the second end 511 of the connector member509 to freely slide therein.

FIGS. 59D-59G show several views of a knob 512 for use with the body 501shown in FIGS. 59A-59C in accordance with an embodiment of the presentdisclosure. The knob 512 includes a ratchet 513 defined by four fingers514. Each of the fingers 514 includes a threaded surface 515 to engage athreaded connecting member 509. The fingers 514 are arched toward a hole516 at the center of the knob 512. The knob 512 also includes fingers517 that engage the second connector 507 (see FIG. 59H). In someembodiments, the body 501 includes a recess 510 to receive the fingers517 on the second connector 508.

FIG. 59H shows an assembly valve 500 that includes the body 501 shown inFIGS. 59A-59C coupled to the knob 512 of FIGS. 59D-59G in accordancewith an embodiment of the present disclosure. The knob 512 is slid ontothe threads of the connecting member 509. The fingers 514 engage thethreads of the connecting member 509 and ratchet onto the connectingmember 509. That is, the knob 512 is freely moveable towards the firstend 508 of the connecting member 509 along the threads of the connectingmember 509, but cannot be moved away from the first end 508 of theconnecting member 509 without rotating the knob 512. That is, the knob512 may be placed onto the connecting member 509 to provide a coarseadjustment of the valve 500 by coarsely moving the connectors 507, 508toward each other to close the valve 500. Because the threaded surfaces515 of the four fingers 514 engage the threads of the connecting member509, rotation of the knob 512 either reduces or increases fluid flowwithin a tube. Each of the fingers 514 includes a threaded surface 515to engage the threads of the connecting member 509 such that rotation ofthe knob 512 moves the second connector 507 toward or away from thefirst connector 506 to thereby control the flow of fluid of a tubepositioned between the support members 502, 503.

FIG. 60 shows a valve 520 having a guiding protrusion 521 in accordancewith an embodiment of the present disclosure. The valve 520 is similarto the valve 500 of FIG. 59H, but includes the guiding protrusion 521and a knob 522 having first and second collars 523, 524. The knob 522also includes internal threads (not shown) to engage threads 525 of aconnecting rod 526. In some embodiments, the internal threads may beratcheting, and in other embodiments, the internal threads may be fixedwithout providing a ratcheting action.

FIG. 61 shows a motor 536 and a valve-securing structure 537 forcoupling to the valve 520 of FIG. 60 in accordance with an embodiment ofthe present disclosure. The valve-securing structure 537 includessecuring fingers 528, 529, 530, 531 each having a curved portion 533 forsnapping onto collars 523, 524 of a knob 522 (see FIG. 62) intorespective collar-guiding portions 534.

Referring now to FIGS. 60, 61, and 62, once the collars 523, 524 aresufficiently secured, the knob 522 is free to rotate. That is, thecollar 523 may be secured between the securing fingers 528 and 530within their respective collar-guiding portion 534 allowing the knob 522to rotate. Likewise, the collar 524 may be secured between the securingfingers 529 and 531 within their respective collar-guiding portion 534allowing the knob 522 to rotate.

When the valve 520 is secured to the valve-securing structure 537,rotation of the wheel 1537 (caused by the motor 536) rotates the knob522 of the valve 520. As the valve 520 flexes, the protrusion 521 freelymoves within the protrusion guide 535 or adjacent to the protrusionguide 535. FIG. 62 shows the valve of FIG. 60 secured to the motor 536via the valve-securing structure 537.

FIG. 63 shows another motor 538 and valve-securing structure 539 forcoupling to the valve of FIG. 60 in accordance with an embodiment of thepresent disclosure. The valve-securing structure 539 includes aprotrusion guide 540 adjacent to the motor 538. The motor 538 is coupledto the wheel 541 to engage the knob 522 (see FIG. 60).

FIG. 64A shows a valve 542 having a slidable collar 545 and severalcompressing fingers 544 for regulating fluid flow through a fluid line543 in accordance with an embodiment of the present disclosure. The base546 is connected to all of the fingers 544. As the slidable collar 545is moved over the compressing fingers 544, the compressing fingers 544compress the tube 543 to impede fluid flow therewithin.

The fingers 544 are coupled to a base 546 such that the base 546 andfingers 544 surround the tube 543. The collar 545 is slidable away fromthe base 546 such that the fingers 544 compress the tube 543 whichthereby reduces an internal volume of the tube 543 as the collar ismoved. The reduction of the internal volume of the tube 543 reduces thefluid flow through the tube. An actuator (not shown) may be coupled tothe collar 545 to control the position of the collar 545 (e.g., a linearactuator may be coupled to the collar 545 and to the base 546). FIG. 64Bshows a cross-sectional view of the valve 542 of FIG. 64A. Note that thefingers 544 may be shaped away from the tube near an opposite end of thebase

FIG. 65 shows a valve 547 having two curved surfaces 549 and 550 forpositioning a fluid tube 548 therebetween to regulate fluid flow throughthe fluid tube 548 in accordance with an embodiment of the presentdisclosure. As the surfaces 549, 550 are compressed together, the tube548 is compressed therebetween. The two curved surfaces 549 and 550 maybe compressed together using an actuator. The tube 548 may be wrappedseveral times around the surface 549.

FIGS. 66A-66G show several views of a valve 551 having a knob 552 tomove a connecting member 553, which is locked into position aftermovement of the knob 552, in accordance with an embodiment of thepresent disclosure.

The valve 551 includes an inner curved, elongated support member 554 andan outer curved, elongated support member 556. A knob 552 is pivotallycoupled to the outer support member 556 via a pin 578. A connectingmember 553 engages teeth 576 of the knob 552.

The connecting member 553 may be inserted into a hole of an end 555 ofthe support member 556 such that rotation of the knob 552 frictionallylocks an engaging finger 700 (see FIG. 66G) into the gear rack 558 ofthe connecting member 553. The engaging finger 700 may engage the teeth576 to lock the knob 552 to thereby prevent rotation of the knob 552unless sufficient torque overcomes the locking action of the engagingfinger 700. A retaining finger 577 is positioned on the other side ofthe hole 571 to press the connecting member 552 against the teeth 576 ofthe knob 552.

The inner support member 554 can pivot out away from the outer supportmember 556 such that a tube can be loaded via raised portions 559 and560 (see FIG. 66C). The inner support member 554 pivots away from theouter support member 556 via dog bone linkers 561, 562, 701, and 702 asshown in FIG. 66C. Thereafter, the inner support member 554 pivots backtowards the support member 556 as shown in FIG. 66D. The connectingmember 553 is then inserted into an end 555 of the outer support member556 (a close up of the insertion is shown in FIG. 66E) that includes theengaging finger 700 that locks onto the teeth 576 of the knob 552 whichtemporarily immobilizes the connecting member 553 (see FIG. 66G). Theother end 581 of the connecting member 553 is locked into a hole 582 ofan end 557 of the support member 556. The connecting member 553 may bepivotally connected to the end 557. The knob 552 includes teeth 576 tomove the connecting member 553 in or out of the end 555. However, whenthe knob 552 is not moved, the engaging finger 700 locks the movement ofthe knob 552 unless a predetermined amount of torque clicks the finger700 to the next tooth of the teeth 576 of the inner portion of the knob552.

As previously mentioned, the support member 554 can swing away from theouter support member 556 as is shown in FIG. 66C, which is facilitatedby the dog bone linkers 561, 562, 701, and 702. The dog bone linker 561includes a pivot hole 572 that couples to a pivot 563 and a pivot hole573 that couples to a pivot 565. The dog bone linker 562 includes apivot hole 575 that couples to a pivot 566 and a pivot hole 574 thatcoupled to a pivot 566. The dog bone linker 701 couples to pivots 567and 570, and the dog bone linker 702 couples to pivots 568 and 569 sothat the end of the support member 556 also swings away from the innersupport member 554.

FIG. 67 shows a graphic 408 that illustrates actuation vs. flow ratesfor a valve in accordance with an embodiment of the present disclosure.The graphic 408 shows the operation of a valve having elongated supportmembers, such as, for example, the valve 340 of FIGS. 49 and 50A-50B,the valve 352 of FIGS. 51A-54, the valve 369 of FIG. 55, the valve 380of FIGS. 56A-56C, the valve 380 of FIGS. 57A-57E, the valve 401 of FIGS.58A-58D, the valve 500 of FIG. 59H, the valve 520 of FIGS. 60-60, thevalve 542 of FIGS. 64A-64B, the valve 547 of FIG. 65, and/or the valve551 of FIGS. 66A-66G. The x-axis of the graphic 408 shows thedisplacement between the ends of the support members of the valve, andthe y-axis shows the flow rate (e.g., caused by gravity and/or apressure source). The response of the valve is a nonlinear function,such as an S-curve, a sigmoid curve, a Gompertz curve, or a generalizedlogistic function. These functions may be adjusted to match the valveand/or the valve may be adjusted to match one of the curves orfunctions.

FIG. 68A shows a flow meter 703 that uses binary optics 705 inaccordance with an embodiment of the present disclosure. The flow meter703 includes a camera 355 that captures one or more images to estimate aflow rate of fluid through a drip chamber 357 using any sufficientmethod, e.g., the methods disclosed herein. The flow meter 703 includesa laser 704 that directs a laser beam onto a binary-optics assembly 705.The binary-optics assembly 705 thereafter redirects and reforms thelaser beam through the drip chamber 357 and onto the image sensor 355such that the image sensor 355 sees a pattern, e.g., the array of lines85 shown in FIG. 8 which may form stripes as shown in the backgroundpattern 89 of FIG. 10. The binary-optics assembly 705 may form thestripes by using a plurality of ovals.

The image sensor 355 may include a filter to filter out all frequenciesexcept for the frequency of the laser 704. For example, the image sensor355 may include an optical, band-pass filter that has a center frequencyequal to (or about equal to) the optical frequency (or center frequencyof the optical frequency) of the laser 704.

The monitoring client 358 may be electrically coupled to the laser 704to modulate the laser 704. For example, the monitoring client 358 mayturn on the laser 704 only when predetermined pixels are being exposedand may turn off the laser 704 when other pixels besides thepredetermined pixels are being exposed.

The flow meter 703 optionally includes a first electrode 800 and asecond electrode 801. The monitoring client 358 may be electricallycoupled to the first and second electrodes 800, 801 to measure acapacitance defined therebetween. In streaming conditions, thecapacitance changes because the relative permittivity is different forair and water. The monitoring client 358 may monitor the changes thatresults from a streaming condition with the drip chamber 357 bymonitoring the capacitance between the first and second electrodes 800,801 and correlate increases and/or decreases of the capacitance beyond athreshold as corresponding to either a streaming condition and/or anon-streaming condition. For example, if the capacitance between thefirst and second electrodes 800, 801 is higher than a threshold, aprocessor within the monitoring client 358 may determine that the dripchamber 357 is undergoing a streaming condition.

In an alternative embodiment, the first and second electrodes 800, 801are loop antennas. The monitoring client 358 uses a transceiver tomonitor the magnetic coupling between the loop antennas 800, 801. Forexample, the transceiver may transmit a coded message from one loopantenna of the antennas 800, 801, to another one of the loop antennas800, 801 and then determine if the coded message was successfullyreceived. If so, then a received signal strength indication (“RSSI”)measurement may be made from the transceiver. See FIG. 68B for anexemplary circuit. The RSSI may be used to monitor the magnetic couplingbetween the antennas 800, 801. If the magnetic coupling is above athreshold, then the monitoring client 358 may determine that a streamingcondition exists within the drip chamber 357. In some embodiments achange of magnetic coupling or a change of capacitive coupling may bedetermined to be an indication that a streaming condition has occurred.

The flow meter 703 may also include a safety valve 706. FIGS. 69A-69Fshow several views of the safety valve 706 that may be used with a flowmeter, such as the flow meter 703 of FIG. 68, in accordance with anembodiment of the present disclosure.

FIGS. 69A-69B show exploded views of a safety valve 706. The safetyvalve may also be referred to as a safety cutoff in this application.The safety valve 706 includes a solenoid 707, an interface structure708, a tube housing 709, a spring 720, a faceplate 712, a first axle713, a second axle 714, a first occluding arm 710, and a secondoccluding arm 711. The faceplate 712 includes a hole 715, and the tubehousing 709 also includes a hole 819. The holes 715, 819 allow the axle713 to slide within the holes 715, 819.

Referring to FIG. 69C, a tube may be placed in location 820 within thetube housing 709 which places the tube in the location 820 next to thefirst and second occluding arms 710, 711, which are easily seen in FIG.69D. A spring 720 keeps the first and second occluding arms 710, 711retracted when in the retracted state (as shown in FIG. 69D), but storesenergy such that a predetermined amount of movement of the first andsecond occluding arms 710, 711 towards the tube 810 causes the spring720 to discharge its stored mechanical energy to cause the first andsecond occluding arms 710, 711 to extend out and occlude the tube inlocation 820.

The spring may be connected to the first and second axles 713, 714. Thespring 720 pulls the first and second axles 713, 714 toward each other.The first and second occluding arms 710, 711 are pivotally connectedtogether. Because the first and second occluding arms 710 and 711 arepivotally together at a pivot point that is off center from the axles713, 714, the spring 720 pulling on the axles 713, 714 toward each otherwill remain stable in the retracted states (as shown in FIG. 69D) untilthe solenoid 707 causes the arms 710, 711 to extend outwards beyond apredetermined amount. As is easily seen in FIG. 69E, a shaft 718 of asolenoid 707 can actuate through a hole 719 to push on the arms 710, 711which causes the spring 720 to release its energy and occlude the tubein location 820 (see FIG. 69F for the case when the where the first andsecond occluding arms 710, 711 are in the occluding position).

Referring to FIG. 69G, in some embodiments, a current responsivematerial 717 may be coupled to the solenoid 707. The current responsivematerial 717 may be configured to the solenoid such that the solenoidmay engage the first occluding arm 710 and the second occluding arm 711when the current responsive material 717 changes shape due to exposureto a change in current. When the current responsive material 717 isexposed to a change in current, the current responsive material 717 willapply force to the solenoid 707. Thereafter, the solenoid 707 may applyforce to the trigger mechanism to release the occluding arms.

In another embodiment, as shown in FIG. 69H, the first and secondoccluding arms may be retained by magnetic force. In some embodiments,first and second magnets 722, 723 may be oriented with opposite magneticpoles aligned (e.g. north and south poles). The arms 710, 711 may beheld in the retracted states using this attractive magnetic force. Oneof the two magnets may be rotated such that the magnets are reorientedso that the first and second magnets are oriented with like magneticpoles aligned (e.g. north and north poles or south and south poles). Thelike pole alignment causes the magnets to repel one another. Themagnetic repelling force may be used to cause the arms 710, 711 toextend outwards. In other embodiments, a permanent magnet 724 may beplaced within a coil 725, as shown in FIG. 69I. In these embodiments,the arms 710, 711 may be retained in the retracted state using themagnetic force created by the magnet 724 and coil 725. The magneticforce may be overcome by using a solenoid or some other element, causingthe arms 710, 711 to be engaged and extend outward beyond apredetermined amount. FIG. 70 shows a flow chart diagram illustrating amethod 728 of estimating drop growth and/or flow within a drip chamberin accordance with an embodiment of the present disclosure. The method728 includes acts 729-735. FIGS. 71A-71E show images taken by a flowmeter with a template overlaid therein to illustrate the method of FIG.70. Note that the template 727 is sued to determine a position of theedge of the drop in the X and Y dimensions.

Act 729 captures an image of a drip chamber. The image captured may bethe image 721 of FIG. 71A. Act 730 positions a template within thecaptured image to a first position. For example, as shown in FIG. 71A, atemplate 727 may be positioned within a predetermined position. Act 731averages all of the pixels within the template 727. Act 732 moves thetemplate to a second position. For example, the template 727 in FIG. 71Amay move the template in the Y direction (e.g., down as seen in FIG.71A).

In act 733, the pixels within the template are used to determine asecond average. In act 734, if a difference between the second averageand the first average is greater than a predetermined threshold value,determine that the template is located at an edge of a drop. Forexample, referring to FIG. 71A, the template may be slowly lowered downin the Y direction, until the template 727 transitions from the edge ofa drop to a portion of the image that doesn't contain the drop, in whichcase the average value of the pixels will transition abruptly to a darkaverage to a lighter average. When this transition occurs, the Yposition of the template 727 is considered to be at the edge of the drop(e.g., Y₁ of FIG. 71A). In act 735, the second position of the drop iscorrelated with a volume of the drop. For example, the Y₁ value may beassociated with a volume of a drop in a lookup table. In someembodiments of the present disclosure, multiple movements of thetemplate 727 are needed to until the edge of the drop is detected. Forexample, the template 727 may be moved in the y-direction one pixel at atime (or several pixels at a time) and several template 727 movementsmay be needed such that the edge of the drop is detected. By monitoringthe edge of the drop, the growth of the drop may be controlled by theflow meter to achieve a target flow rate (e.g., the rate of thetransition between Y1 of FIG. 71A to Y2 of FIG. 71B may be controlled bya PID control loop within a flow meter). FIG. 71B shows a location, Y₂,that corresponds to a growth in the drop relative to the location, Y₁,of FIG. 71A. FIGS. 72C-73E show how the sequential growth of a drop maybe monitored.

FIG. 72 shows a modulatable backlight assembly 740 in accordance with anembodiment of the present disclosure. The assembly 740 may be thebacklight 18 of FIG. 1 or may be used as a backlight for any sufficientflow meter disclosed herein. The assembly 740 includes a first circuitboard 738, a second circuit board 739, a first backlight diffuser 736,and a second backlight diffuser 737.

The first circuit board 738 includes embedded light sources 822 thatextend along the interface between the first backlight diffuser 736 andthe first circuit board 738. The embedded light sources 822 shine lightinto the first backlight diffuser 736 which is directed outwards asindicated by 821. The light 821 may be directed towards an image sensor.The first backlight diffuser 736 only diffuses light with no “pattern”formed when viewed by an image sensor.

The second circuit board 739 includes embedded lights 823 which areshined into the second backlight diffuser 737. The second backlightdiffuser 737 creates a pattern of stripes that shows up in the light 821when viewed by an image sensor. Therefore, a monitoring client (e.g.,the monitoring client 358 of FIG. 51A) and/or a flow meter (e.g., theflow meter 7 of FIG. 1) can select between a striped background pattern(by activating the embedded lights 823) and a non-striped backgroundpattern (by activating the embedded lights 822).

For example, referring now to FIGS. 1 and 72, the flow meter 7 may usethe backlight assembly 740 in some specific embodiments; The flow meter7 may use a non-striped backlight pattern (by activating the embeddedLEDs 822 without activating the embedded LEDs 823) to monitor the growthof drops and may switch to a striped background pattern (by activatingthe embedded LEDs 823 without activating the embedded LEDs 822) todetect streaming conditions.

FIGS. 73A-73C show several views of a tube-restoring apparatus 741 inaccordance with an embodiment of the present disclosure. The apparatus741 includes a drive gear 744 that is coupled to a first restoring gear742. The first restoring gear 742 is mechanically coupled to a secondrestoring gear 743. A tube may be placed between the first and secondrestoring gears 742, 743. Portions of the first and second restoringgears 742, 743 define a space 745 in which a tube may be positioned.Rotation of the first and second restoring gears 742, 743 closes thedistance between the space 745 when the tube is positioned between thefirst and second restoring gears 742, 743. The transition from anon-restoring position to a restoring position is shown in FIG. 73B toFIG. 73C. For example, a tube may be positioned such that an occluderpresses against the tube from the bottom up (as shown in FIG. 73B). Ifthe tube becomes distorted over time, a motor connected to the drivinggear 744 rotates the gears 743 and 744, to press against the walls ofthe tube (as shown in FIG. 73C) to restore the tube such that across-section of the tube has a general circular shape by compressing onthe wall portions of the tube that are expanded beyond a center axis ofthe tube such that the tube is distorted into an oval shape, forexample.

FIG. 74 shows a system for regulating fluid flow 746 using a valve 747having two flexible strips 753 and 754 (see FIG. 75); And FIG. 75 showsthe valve 746 of FIG. 74 in accordance with an embodiment of the presentdisclosure. Optionally, a motor may be attached to the valve 746 forcontrol by a flow meter in one embodiment.

As shown in FIG. 75, the valve 747 includes two flexible strips 753, 754in which a tube may be disposed therebetween, a guiding shaft 752, twoguidable members 749, 750, a screw 791, and a knob 748.

When the knob 748 is turned, the screw 791 rotates. Rotation of thescrew 791 pulls the distal guiding member 750 toward the proximalguiding member 749 (because the distal guiding member 750 includesinternal threads and the screw 791 spins freely within the proximalguiding member 749). The guide 752 guides the movement of the distalguiding member 750. The guide 752 is coupled to the proximal guidingmember 749.

FIG. 76A shows a valve 755 that utilizes a fluid-based bladder 758 inaccordance with an embodiment of the present disclosure. The valve 755includes two clamshells 756, 757, a bladder 758, and a piston 759. Thepiston 759 may be any fluid source. The bladder 758 may be placed withina cavity 764 and a tube may be placed across the bladder 758 andpositioned within the throughways 760 and 761. Thereafter, the clamshell757 may be placed over the bladder 758 such that the cavity 765 isplaced over the bladder 758. The two clamshells 756, 757 may then beultrasonically welded together, temporarily compressed together, and/orsufficiently held together. Thereafter, an actuator (e.g., an actuatorcontrolled by a flow meter disclosed herein) may be actuated to movefluid in and out of the bladder 758 via the piston 759.

FIG. 76B shows a cross-sectional view of the assembled valve 755 of FIG.76A with two elastomeric fillers 1002, 1004 in accordance with anembodiment of the present disclosure. The elastomeric fillers 1002, 1004help hold the tube 1000 into position and help restore the tube 1000when the bladder 758 is deflated.

FIG. 77 shows a system 766 for regulating fluid flow using a valve 769having two flexible strips 771, 772 (see FIG. 79) actuatable by a linearactuator 822 in accordance with an embodiment of the present disclosure.FIG. 78 shows the linear actuator 822 actuating the valve 769 to impededfluid flow through a tube 775. The valve 769 is coupled to two couplers767 and 768. The proximal coupler 768 moves with the linear actuator 822while the distal coupler 767 is fixed relative to a non-moving end ofthe linear actuator 822.

FIG. 79 shows a close-up of the valve 769 of FIGS. 77-78. The valve 769includes two strips 771, 772 (which may be metallic strips) in which thetube 775 may be disposed. The two strips 771, 772 of the valve 769 maybe coupled to a first end structure 773 and a second end structure 774.The first end structure 773 may be coupled to the distal coupler 767 andthe second end structure 774 may be coupled to the proximal couplerproximal coupler 768 (see FIGS. 77-78). A string 770 or membrane may bewrapped around the tube 775 such that, when the strips 771, 772 arestraightened out, the string 770 presses against the side walls of thetube 775 to help round the tube 775. The membrane may be a flexible, butnot stretchable, material (or minimally stretchable material). FIG. 80shows a close-up of the valve as actuated in FIG. 78. Note the holes 776and 778 that the string 770 is threaded through. The string 770 (whichmay metallic) is spiraled around the tube 775 such that when the valve769 opens, the string 770 restores the tube 775.

FIG. 81 shows several images for use to illustrate a method ofestimating drop growth and/or fluid flow illustrated in FIGS. 82A-82B inaccordance with an embodiment of the present disclosure. FIG. 81 showsimages 771-777 which are referred to below regarding FIGS. 82A-82B.

FIGS. 82A-82B show a flow chart diagram illustrating a method 803 ofestimating drop growth and/or fluid flow. The method 803 includes acts804-818.

Act 804 captures a first image (e.g., image 771 of FIG. 81). The firstimage may be a grey scale image of the drip chamber. The drip chambermay be uniformly lit with a striped pattern on the bottom of the chamber(i.e., there is no back pattern on the top portion of the drip chamber).

Act 805 creates a first thresholded image using the first image. Thefirst thresholded image may be the image 774 of FIG. 81. The firstthresholded image may be made by comparing each pixel from the firstimage to a threshold value (e.g., setting a respective pixel of thethresholded image to 0 if the respective pixel of the first image isabove the threshold or setting a respective pixel of the thresholdedimage to 1 if the respective pixel of the first image is below thethreshold). This act is to highlight areas where there is water in frontof the background.

In some specific embodiments, the threshold level is updated every timea new image is taken to ensure a predetermined ratio of 1 to 0 pixels ismaintained to highlight the drop. The ratio may be updated for use byact 805 when used again or the update may adjust the threshold until apredetermined ratio of 1 to 0 pixels is made and then use the firstthresholded image for the rest of the method 803.

Act 806 determines a set of pixels within the first thresholded imageconnected to a predetermined set of pixels within the first thresholdedimage. The predetermined set of pixels may be determined by fiducialsmarked on the drip chamber or an opening in which drops are formed. Thepredetermined set of pixels may be a predetermined set of x, y valuesthat correspond to pixels. Act 806 may use a connected component imageanalysis algorithm.

Act 807 filters all remaining pixels of the first thresholded image thatare not within the set of pixels. The filter operates on apixel-by-pixel basis within the time domain to generate a first filteredimage. The first filtered image is an estimate of a non-active (e.g., aresult from features not of interest in the image) portion of the firstthresholded image (image 774 of FIG. 81). The filter may be any filter,e.g., any filter described herein.

Act 808 removes pixels determined to not be part of a drop from thefirst thresholded image using the first filtered image to generate asecond image (e.g., image 775 of FIG. 81). A pixel within the secondimage will be set to 1 if a respective pixel in the first thresholdedimage is 1 and a respective pixel in the first filtered image is lessthan 0.5; otherwise, the pixel will be set to 0.

Act 809 determines a second set of pixels within the second imageconnected to a predetermined set of pixels within the second image togenerate a third image (e.g., the image 776 of FIG. 81). The third imageidentifies the second set of pixels within the second image. Act 809finds the set of “lit” pixels in the second image connected to thepredetermined set of pixels (e.g., pixels representing the opening inwhich drops are formed).

Act 810 determines a first length of the drop by counting the number ofrows containing pixels corresponding to the second set of pixels withinthe third image. That is, the drop length is determined to be equal tothe last “lit” row in the set of pixels found in Act 809. The firstlength corresponds to a first estimated drop size.

Act 811 updates a background image using the first image. A low-passfilter may be used to update each pixel's value in the background image.An infinite impulse response filter may be used to update the backgroundimage using the first image. A pixel is only updated in the backgroundimage for rows below the first length plus a predetermined safety zone.A pixel in the background image is updated by low pass filtering thevalue from the corresponding pixel in the first image.

Act 812 creates a second thresholded image (e.g., image 772 of FIG. 81)by comparing the first image with the background image. That is, thefirst image has the background image subtracted from it, and on apixel-by-pixel basis, the absolute value of each pixel is set to 1 if itis above a second threshold value and is set to a 0 if it is below thesecond threshold value to generate the second thresholded image.

Act 813 sums the rows of the second thresholded image to create aplurality of row sums (see image 773 of FIG. 81). Each row sumcorresponds to a row of the second thresholded image.

Act 814 starts at a row position of the second thresholded image havinga first sum of the plurality of sums that corresponds to the firstlength. The row position is incremented in act 815. Act 816 determineswhether the present row position correspond to a corresponding row sumthat is below a threshold, e.g., zero. If no, then act 815 is preformedagain until the present row position corresponds to a corresponding rowsum that is zero and then the method 803 proceeds to act 817.

Act 817 determines a second length is equal to the present row position.The second length corresponding to a second estimated drop size. Act 818averages the first and second lengths to determine a average length. Theaverage length corresponding to a third estimated drop size. By usingthe first and second lengths to determine an average length, the effectsof condensation on the inner walls of the drip chamber are mitigated.That is, the purpose of creating two estimates of drop length is tocompensate for how each length is affected by the presence ofcondensation. The first length tends to underestimate drop length if adrop of condensation intersects the growing drop from the spigot. Thesecond length tends to overestimates the drop length if the drop ofcondensation intersects the growing drop from the spigot. Their averageprovides a better estimate when condensation is present. In the absenceof condensation, the estimates are almost equal. In other embodiments,only either the first or second length is used to estimate the dropsize.

FIG. 83 shows a flow chart diagram of a method 900 for reducing noisefrom condensation in accordance with an embodiment of the presentdisclosure. Method 900 includes acts 902-910.

Act 902 captures an image of a drip chamber. Act 904 performs a canny,edge-detection operation on the image to generate a first processedimage. Act 906 performs an AND-operation on a pixel on a first side ofan axis of the first processed image with a corresponding mirror pixelon the second side of the axis of the first processed image. That is,Act 902 defines an axis in the first process image, and performs an ANDon each pixel on one side with a pixel on the other side, such that thepixel on the other side is symmetrical with the pixel on first side. Forexample, a 40 (X-axis) by 40 (Y-axis) image may have an axis definedbetween pixel columns 19 and 20. The top, left pixel would be pixel(1,1) A pixel at location (1,5) would be AND-ed with a pixel at (40,5).The resulting pixel would be used for both locations (1,5) and (40,5) togenerate the second processed image.

After act 906 is performed, act 908 determines whether all of the pixelshave been processed. Act 908 repeats act 906 until all pixels have beenprocessed. Act 910 provides a second processed image that is the resultsof all of the AND operations.

FIG. 84 shows another valve 2000 for use with a flow meter in accordancewith an embodiment of the present disclosure. The valve 2000 is coupledto a portion of an inlet fluid line 2001 and a portion of an outletfluid line 2002. A section of flexible tube 2003 is coupled between theportion of an inlet fluid line 2001 and a portion of an outlet fluidline 2002 within a rigid cylinder 2004. A fluid pump 2005 is coupled tothe rigid cylinder 2004 to pump fluid into and out of the rigid cylinder2004. The rigid cylinder 2004 may include a fluid disposed therein,e.g., a liquid.

An actuator 2007 controls a plunger 2008 of the pump 2005 to use thefluid within the rigid cylinder 2004 to compress the flexible tubesection 2003 to control the flow of fluid between the portion of aninlet fluid line 2001 and a portion of an outlet fluid line 2002. Theactuator 2007 may be controlled by a processor (e.g., the processor 15of FIG. 1). By collapsing the flexible tube section 2003, flow of fluidflowing within the flexible tube section 2003 may be controlled byactuation of the actuator 2007.

FIGS. 85A-85C show another valve 8500 for use with a flow meter inaccordance with an embodiment of the present disclosure. This embodimentuses a plunger 8512 and a substantially incompressible filler 8621 (thefiller was left out of FIGS. 85A-85C for clarity and is shown in FIG.86) to deform a flexible tube in which flow is being controlled. Theflexible tube may be an IV tube and may be disposed thorough holes 8518(see FIG. 85B) on the first clamshell portion 8504 and/or the secondclamshell portion 8502. The substantially incompressible filler 8621(see FIG. 86) is contained within a rigid casing comprising a firstclamshell portion 8504 and a second clamshell portion 8502. The firstclamshell portion 8504 and second clamshell portion 8502 are connectedby a hinge 8505 that allows a user to open the casing to insert andremove a flexible tube in which fluid flow is being controlledtherethrough by the valve 8500. The plunger 8512 engages thesubstantially incompressible filler 8621 through a hole 8511 in thefirst clamshell portion 8504, ultimately deforming the tube.

The first clamshell portion 8504 and second clamshell portion 8502 aresecured in a closed position by a latch (8503, 8506) once the flexibletube is positioned in the housing. The latch comprises a male component8503 on the second clamshell portion 8502 and a female component 8506 onthe first clamshell portion 8504. The male component 8503 extends outfrom second clamshell portion 8502 on the side opposite the pivot asmultiple fingers. The female component 8506 is a lever with an input end8506 a and an output end 8506 b. The latch secures the clamshell 8502,8504 closed by positioning the output end 8506 b of the female component8506 over the male component 8503, and rotating the female component8506 onto the top of the second clamshell portion 8502 as depicted inFIG. 85B. The connecting members 8501 connect the female portion 8506 tothe first clamshell portion 8504 such that when the female component ofthe latch is rotated closed, the output end 8506 b of the femalecomponent's 8506 rounded edge (i.e., the output end 8506 b is a roundededge) compresses against the male component 8503 of the latch 8503,8506. This feature creates a force on the male component 8503 when thefemale portion 8506 is rotated, which squeezes the first clamshellportion 8504 and second clamshell portion 8502 together.

The plunger 8512 is guided into the first clamshell portion 8504 by aguide 8508 attached to the first clamshell portion 8504 and is poweredby a linear actuator 8510. The guide 8510 aligns the plunger 8512 withthe hole 8511 in the first clamshell portion 8504. The actuator 8510 isattached to the guide 8508 on an end of the guide 8508 that is oppositeto the end of the guide 8508 attached to the first clamshell portion8504.

FIG. 85C shows a portion of the valve 8500 with parts removed forclarity. As shown in FIG. 85C, the plunger 8512 is connected to theoutput shaft 8520 on the actuator 8510 which drives the plunger 8512 inand out of the first clamshell portion 8504. Springs 8516 are placedin-between the plunger stabilizing arms 8514 and the actuator 8510 tourge the plunger 8512 away from the actuator 8510. The springs 8516 helpcounter act the force put on the plunger by the filler 8621 (see FIG.86) allowing an actuator 8510 that exerts less peak force.

In some embodiments of the present disclosure, the plunger head 8512 ahas a smaller area than the longitudinal cross-section of the tubewithin the valve housing 8502, 8504. The smaller head 8512 a results ina smaller change in pressure when compared to similar displacement witha larger head. In some embodiments, this may allow for more precisechanges in tube deformation by the actuator 8510.

The first clamshell portion 8504 and second clamshell portion 8502 havesemicircular cutouts on the sides adjacent the hinged side to create theholes 8518 (see FIG. 85B). The cutouts are positioned to align when thecasing is in the closed position, creating the hole 8518. The hole 8518allows a flexible tube (such as a PVC IV tube) to go through the closedrigid casing 8502, 8504 without being deformed.

FIG. 86 shows a cross-sectional view of the valve housing with thesubstantially incompressible filler 8621 enclosed therein. Thesubstantially incompressible filler 862 is enclosed in the first andsecond clamshell portions 8502, 8504. The first layer 8628 and secondlayer 8626 lay within the first clamshell portion 8504, while the thirdlayer 8624 and fourth layer 8622 lay within the second clamshell portion8502. The second layer 8626 and third layer 8624 lay in the middle whenthe casing is closed and form a conduit 8618, in which the tube isplaced, to aid in consistent deformation of the tube. The conduit 8618connects the holes 8618 defined by the closed clamshell portions 8502,8504.

The materials used to make some flexible tubes may be susceptible tocreep, which affects the tube's ability to rebound back to its originalshape after multiple deformations. The second layer 8626 and third layer8624 are stiffer than the first layer 8628 and fourth layer 8622 inorder to consistently reform the tube when creep starts to affect theshape of the tube. The stiffer second layer 8626 and third layer 8624are affected less by creep than the tube and will reform back to theiroriginal shape after many deformations. Therefore, when the filler 8621is trying to reform the original shape of the conduit 8618, it willreform the tube within the conduit.

Also, in some embodiments, the tube has a tendency to stick to its selfwhen deformed to a point where the inner surfaces of the tube contacteach other. This makes it difficult to control very low drip rates whenthe tube is almost completely closed. The stiff layers surrounding thetube 8624, 8626 apply forces sufficient to overpower the stickingforces, which thereby results in the tube opening uniformly.

The first layer 8528 and fourth layer 8522 fill the space between thesecond layer 8526 and third layer 8524, and the clamshell portions 8502,8504. The second layer 8526 and the third layer 8524 are softer in orderto spread the force of the plunger 8512 evenly throughout the wholesection of tube within the clamshell portions 8602, 8504. Instead oftranslating the force directly to the area of the tube immediately abovethe plunger 8512, the plunger 8512 increases the pressure in theclamshell portions 8602, 8504. This causes substantially uniformdeformation of the enclosed section of the tube. Uniform deformation isadvantageous because frictional forces between the liquid and the tubehelp with the valves flow rate precision. A longer deformed sectionimparts more frictional force on the liquid flowing through, slowing itsflow rate. Extending the section of the tube being valved allows for alow flow rate with a larger, more manageable lumen diameter.

The soft layers 8622, 8628 preferably have a shore OO hardness fromabout 20 to about 25. The hard layers preferably have a shore A hardnessof about 15. In some embodiments, preferred materials for the fillerinclude silicone, urethane, viton, or nitrile.

FIGS. 87A-87D show a flow control apparatus 8700 in accordance with anembodiment of the present disclosure. The flow control apparatus 8700includes an apparatus casing 8702 which encloses a valve 8732 and asafety cutoff 8734 (see FIG. 87B). As is easily seen in FIG. 87B, thecasing 8702 includes a door 8702 b and a body 8702 a. A drip chamberholster 8714 having a top component 8714 a and a bottom component 8714 bis attached to the body 8702 a and is configured to orient the dripchamber vertically. A laser 8708 and diffracting device 8716 areattached to the body 8702 a of the casing 8702 and are aligned todiffract the laser light so it creates a pattern on a drip chamberloaded in the drip chamber holster 8714 (drip chamber not shown in FIG.87). An image sensor 8710, having the drip chamber and diffractionpatterns in its field of view, is also attached to the apparatus casing8702.

In some embodiments, the laser beam is first split by a beam splitterinto first and second beams such that a first beam is directed toward anupper diffracting device 8716 a and the second beam is directed toward alower diffracting device 8716 b. The beam splitter may be part of thelaser beam exit lens.

The upper diffracting device 8716 a directs its pattern at an uppersection of the drip chamber and the lower diffracting device 8716 bdirects its pattern at a lower section of the drip chamber. Thediffracting devices 8716 a, 8716 b may use, in some embodiments,binary-optic films to redirect and reform the laser beams into patterns.The upper film of the upper diffracting device 8716 a converts the beaminto an array of dots, or in some embodiments, a single dot. Thiscreates the contrast for the image sensor 8710 to track the growth ofthe drop developing at the top of the drip chamber. The lower film ofthe lower diffracting device 8716 b converts the beam into a pattern ofhorizontal stripes. The stripes create the contrast for the image sensor8710 to determine if the fluid is streaming instead of dripping.

As is easily seen in FIG. 87B, this embodiment has a valve closing arm8720 connected to the door 8702 b of the casing 8702 and to the inputend 8722 a of the female latch component 8722. When the door 8702 b isopened, the closing arm 8720 pulls on the input end 8722 a of the femalelatch component 8722 causing it to rotate up and away from the valve8732. This releases the pressure put on the valve 8732 from the outputend 8722 b of the female latch component 8722. Once the female latchcomponent 8722 disengages the male latch component 8728, the closing arm8720 pulls open the valve casing clamshells 8732 a, 8732 b by pullingthe female latch component 8722 away from the valve 8732. When the door8702 b is completely open, the clamshells 8732 a, 8732 b are open farenough for an operator to remove or insert a tube being valved into thevalve 8732 (the open position is shown in FIG. 87B). Once a tube isplaced in the valve 8732, an operator closes the door 8702 b. Closingthe door 8702 b causes the closing arm 8720 to engage the female latchcomponent 8722 such that the output end 8722 b of the female latchcomponent 8722 mates with the male latch component 8728 whereby furtheractuation rotates the female latch 8722 component into a securedposition (similar to the position of the valve 8500 shown in FIG. 85B).The closing arm 8720 adds efficiency to the process of rigging theapparatus 8700 and improves safety by insuring the valve 8732 issecurely closed when the door 8702 b is closed.

The operator lays the tube through the safety cutoff 8734 (physicalmechanics of the safety cutoff are described with regards to FIG. 69)along with the valve 8732 when rigging the apparatus 8700 (refer to FIG.87C). The safety cutoff 8734 uses spring powered occluding arms 8739 a,8739 b to compress the tube into a backstop 8741 when triggered. Asolenoid applies the force to trigger the mechanism and release theoccluding arms 8739 a, 8739 b. Once the occluding arms 8739 a, 8739 bare released, they substantially cutoff flow through the tube, andultimately to the patient, by compressing the tube against the back stop8741. The safety cutoff 8734 is triggered by a processor which uses asafety sensor to sense unplanned events. The unplanned events mayinclude power loss, the apparatus 8700 falling over, the fluid streamingthrough the drip chamber, or the flow rate not properly correlating tothe valve's 8732 position. The latter of these examples may address asituation where the tube is kinked at some point between the apparatusand the patient.

A safety cutoff resetting arm 8735 may be attached to the door 8702 band is configured to reset the safety cutoff valve 8734 to the free flowposition by opening the door 8702 b of the casing 8702. The safetycutoff valve 8734 used in this embodiment is similar to the valvedescribed in FIG. 69. However, in FIG. 87, the occluding arm 711 in FIG.69 is extended past the screw 714 of FIG. 69 creating a tab projectingout of the bottom. The safety cutoff valve 8734 of FIG. 87B includesthis tab 8740 as shown in FIG. 87C.

Referring to FIG. 87C, the resetting arm 8735 includes three members8736, 8738, 8742. A first member 8736 of the resetting arm 8735 isattached to the door 8702 b and to a second member 8738 of the resettingarm 8735. The second member 8738 of the resetting arm 8735 is attachedto a third member 8742 of the resetting arm 8735. Opening the door 8702b actuates the first member 8736, which in turn actuates the secondmember 8738 and the third member 8742. The third member 8742 has aprojection configured to engage the tab 8740 and urge it back to thenon-engaging parallel position (as shown in FIG. 69D) when it engagesthe tab 8740. In additional embodiments, resetting the safety cutoff8734 can be accomplished with less or more members if desired.

FIG. 87D shows an embodiment of the present disclosure designed to stopfluid flow through the valved tube when the door 8702 b is in an openposition. A compression tab 8744 may be used to substantially cutoffflow through the tube being valved when the apparatus casing door 8702 bis open. When installing a tube, an operator inserts the tube into theslit 8745 between the compression tab 8744 and the casing body 8702 a.When the door is open, the full force of the compression tab 8744 isexerted onto the tube, substantially cutting off flow by deforming thetube. When the door 8704 b is closed, a wedge 8746 attached to the door8702 b is forced into the slit 8745 and wedges the compression tab 8744open. Wedging open the tab 8744 allows the tube to reopen permittingfluid flow. This feature is used as a safety mechanism to make sure noliquid from the drip chamber is administered to the patient when anoperator is rigging the apparatus.

Actuating the valve 8732 causes minor pressure changes in the apparatuscasing 8702. An array of holes 8748 may be defined in the apparatuscasing body 8702 a. These holes allow the pressure inside the casing toequalize the pressure outside the casing 8702, which may increaseaccuracy in some embodiments.

Referring again to FIG. 87A, in some embodiments of the presentdisclosure, a status light 8718 may be used to visually display thestatus of the flow control apparatus 8700. The light 8718 is attached tothe flow control apparatus 8700 at a location that can readily be seenby a nearby person. In some embodiments, the status light 8718 will emita first color when the fluid is flowing and a second color when flow hasstopped. In other embodiments, the status light 8718 will emit a firstcolor when the flow control apparatus 8700 is operating properly, asecond color when the flow control apparatus 8700 has detected aproblem, and a third color when the flow control apparatus 8700 ispaused. The status light 8718 may also be configured to flash ever timea drop falls in the drip chamber. This feature allows an operator to seethe drip rate from a distance where it would not be possible to read thedisplay 8704.

Certain embodiment of the present disclosure may use a battery as apower source. Other embodiments can us a combination of a battery and anAC wall adapter, or just and AC wall adapter.

In another embodiment of the present disclosure, the apparatus 8700includes input buttons 8706 and a display 8704. The input buttons 8706can be used to control the flow of liquid through the drip chamber. Thisallows an operator to set the flow rate initially and adjust the flowrate when desired. In other embodiments, input buttons 8706 may beconfigured to adjust any adjustable parameter of the apparatus 8700. Theinput buttons 8706 may be lit up in different colors to aid a user. Forexample, a green input button of the input buttons 8706 may be used toincrease or decrease the flow rate, the a yellow button of the inputbuttons 8706 may be used to pause the flow, and a red button of theinput buttons 8706 may be used to stop the flow of fluid. The display8704 can display infusion information including the current flow rateand set flow rate, to inform an operator. The display 8704 may alsodisplay information regarding the patient, the device, or the fluidbeing delivered by the device. For example, the status of the batteries,any alarms, or the patient's identification sequence.

A processor may also be in communication with a status light 8718. Theprocessor may tell the status light 8718 to emit a first color whenfluid is flowing and a second color when flow has stopped. The statuslight 8718 may also emit a first color light when the pump isoperational and a second color light when a problem has been detected.The first color will likely be green and the second color will likely bered.

Certain embodiments may use an audio output device to communicate withan operator. For example, this device may signal an error, update anoperator on the status of the pump, or guide an operator through a setup of the flow control apparatus 8700.

Referring now to FIGS. 88A-88E: FIG. 88A shows a perspective view of afluid flow apparatus 8800 used to control fluid flow through a dripchamber 8820 connected to a tube 8821, wherein the apparatus 8800 hasthe casing door 8809 b open; FIG. 88B shows a perspective view of onlythe valve 8801 from FIG. 88A; FIG. 88C shows the inner workings of thevalve 8801 from FIG. 88B; FIG. 88D shows a simplified diagram illustratethe operation of the valve cutoff mechanism in a door 8809 b closedposition; and FIG. 88E shows a simplified diagram to illustrate thevalve cutoff mechanism in the door 8809 b open position in accordancewith an embodiment of the present disclosure.

The flow control apparatus 8800 impedes flow through a tube 8821 withinthe valve 8801 when the casing door 8809 b is open. The casing door 8809b is pivotally coupled to the casing body 8809 a In this embodiment, theactuator 8802 and attached plunger 8816 (see FIG. 88c ) are connected tothe valve 8801 by cutoff springs 8806 (see FIG. 88B) that urge theplunger 8816 into the filler disposed within the valve 8801 housing. Theplunger 8816 is attached to the actuator 8802 by a threaded driveshaft8812, and, in some embodiments, is able to freely rotate on the driveshaft 8812. This allows the plunger 8816 to keep a constant orientationwhile the driveshaft 8812 rotates. A half-nut 8811 on the end ofengaging member 8810 is operatively connected to the fluid flowapparatus 8800 such that the half-nut 8811 has the ability to engage anddisengage the threaded driveshaft 8812 with the threads of the threadedhalf nut 8811.

When the apparatus casing door 8809 b (see FIG. 88A) is closed, thehalf-nut 8811 (see FIG. 88C) is engaged with the driveshaft 8812 toallow the actuator 8802 to control the position of the plunger 8816 byrotating the threaded driveshaft 8812. Opening the apparatus casing door8809 b (see FIG. 88A) disengages the half-nut 8811 (see FIGS. 88B-88C)from the drive shaft 8812 (by actuating the half nut 8811 away from thedrive shaft), leaving only the cutoff springs 8806 to control theposition of the plunger 8816. The cutoff springs 8806 drive the plunger8816 into the filler with enough force to substantially cutoff fluidflow through the tube 9921 coupled to the drip chamber 8820 (also seeFIG. 88A). This mechanism may serve the same purpose as the compressiontab described in FIG. 87.

FIGS. 88D-88E illustrate the mechanism that engages and disengages thehalf-nut 8811 with the threaded driveshaft 8812. An engaging member 8810has a half-nut 8811 at one end and pivotally connected to a pivotingmember 8803 at the other end. The pivoting member 8803 is anchored by ahinge 8818 (coupled to the casing body 8809 a) and is positioned to beengaged by an urging component 8805 connected to the casing door 8809 b.The urging component 8805 is coupled to the door 8809 b (shown in FIG.88A).

FIG. 88D shows the position of the mechanism when the casing door 8809 bis closed. In this position, the urging component 8805 is not engagedwith the pivoting member 8803, leaving only the force of the spring 8814to influence the position of the pivoting 8803 and connected engaging8810 members. The spring 8814 biases the pivoting member 8803 to rotatein the counter clockwise direction, with respect to the view of in FIG.88D. The rotational force translates to a force pushing on the engagingmember 8810 into the threaded driveshaft 8812 due to the hinge 8818.

FIG. 88E shows the position of the mechanism when the casing door 8809 bis open. Opening the door 8809 b causes the urging component 8805 torotate and engage the pivoting member 8803. This counteracts the forceof the spring 8814 and rotates the pivoting member 8803 clockwise, withrespect to the view of FIG. 88E. The clockwise rotation of the pivotingmember 8810 disengages the engaging member 8803 from the threadeddriveshaft 8812.

FIG. 89 shows a method for controlling fluid flow through a drip chamberin accordance with an embodiment of the present disclosure. The methodincludes an installation act 8902. During the installation act 8902 aflexible tube in fluid communication with a drip chamber issubstantially deformed while being installed in a fluid flow controlapparatus by an operator. At reformatting act 8904, the tube is reformedto substantially it initial size once the installation process iscomplete. At imaging act 8906, images are captured of the drip chamberin fluid communication with the tube. At estimating act 8908, the imagesfrom the previous act are used to estimate flow rate through the dripchamber. At communicating act 8910, the estimated flow rate iscommunicated to a fluid monitoring client. At receiving act 8912, adesires flow rate is received from a used. The user may be a fluidmonitoring client or a device operator. At comparing act 8914, theestimated flow rate is compared to the desired flow rate and adifference is produce. At determining act 8916, the magnitude anddirection of valve actuation to achieve the desired flow rate aredetermined using the difference from the previous act.

Referring now to FIG. 89B, at actuating act 8918, the valve is actuatedin accordance with the determined magnitude and direction to achieve thedesired flow rate. Valve actuation may be achieved by increasingpressure around a defined section of the tube which deforms the tube andmodifies the shape of the lumen within the tube. Pressure adjustment maybe achieve by disposing a rigid housing around a defined section of thetube and engaging a plunger with a substantially incompressible fillermaterial enclosed within the housing. The filler material translates theengaging plunger to pressure within the housing thereby deforming thetube.

At lighting act 8920, a light is emitted to indicate the status of theapparatus performing this method. A first color of light may be emittedto indicate fluid is flowing and a second light may be emitted toindicate flow has stopped. A first color of light may be used toindicate the apparatus is functioning properly and a second light may beused to indicated a problem has been detected.

At monitoring act 8922, the method monitors for unplanned events.Unplanned events may be power loss or an apparatus performing thismethod falling over. At cutoff act 8924, fluid flow through the dripchamber is stopped when an unplanned event is detected by the monitoringact. At removing act 8926, the tube is deformed to substantially reduceits lumen size while it is being removed from an apparatus performingthis method.

As shown in FIG. 90, a system 9000 is shown. The system 9000 may be usedwith the flow control apparatus 8700 of FIGS. 81A-87D or the flowcontrol apparatus 8800 of FIGS. 87A-87D. The system 9000 includes aprocessor 9002 in communication with the image sensor 9006 and the valveactuator 9004. The processor 9002 receives image data from the imagesensor 9006. Once the processor 9002 has received the image data fromthe image sensor 9006, the processor uses the data to estimate a flowrate. The processor 9002 then compares the estimated flow rate to adesired flow rate, and produces a difference between the two values. Theprocessor 9002 adjusts the valve actuator 9004 based on the value toachieve the desired flow rate.

The processor 9002 may also be in communication with a safety sensor9008 and the safety cutoff 9010. In this embodiment, the processor 9002receives data from the safety sensor 9008 and determines when fluid flowshould be stopped based on predetermined criteria (such as power loss,streaming, or device malfunction). Once the processor determines fluidflow should be stopped, it triggers the safety cutoff 9010.

The processor 9002 may also be in communication with the input buttons9012. The processor 9002 receives data from the input buttons 9012 anduses that data to control the valve actuator 9004 or trigger the safetycutoff 9010. For example, when the operator presses the increase flowbutton 9012 the processor 9002 receives a signal from the button 9012and adjusts the valve actuator 9004 accordingly, or when the operatorpresses the stop button 9012 the processor 9002 receives a signal anddirects the safety cutoff 9010 to trigger. The processor 9002 may alsosend data to the input buttons 9012, such as data related to which colorthe button should light up.

The processor 9002 may also be in communication with the display 9014.The processor 9002 receives data from the various components of theapparatus such as the valve actuator 9004, the safety sensor 9008, theimage sensor 9006, or the input buttons 9012 and then output the data inhuman readable form on the display 9014. For example, the processor 9002receives data from the image sensor 9006, estimates a flow rate, anddisplays the estimated flow rate on the display 9014.

The processor 9002 may also be in communication with the status light9018. The processor 9002 receives data from various components of theapparatus such as the valve actuator 9004, the safety sensor 9008, theimage sensor 9006, or the input buttons 9012, creates a signal forsending to the status light 9018 based on the data, and outputs thesignal to the status light 9018. Examples include, blinking the light9018 every time a drip drops in the drip chamber, turning the light 9018green when the pump is operational, turning the light 9018 yellow whenthe pump is paused, or turning the light 9018 red when the pump is notoperating correctly.

The processor 9002 may also be in communication with a power supply orbattery 9016. The processor 9002 receives data from power supply orbattery 9016 regarding power output. For example, receiving voltage fromthe battery 9016 to estimate how much charge it has. The processor 9002may also send data to the power supply 9016 to adjust its power output.

FIG. 91 shows an apparatus 9100 configured to control fluid flow througha drip chamber connected to a tube and communicate with an RFIDinterrogator in accordance with an embodiment of the present disclosure.The apparatus 9100 may transmit data to and from a commerciallyavailable radio frequency identification (RFID) interrogator without theuse of a dedicated RFID tag.

As shown in FIG. 91, a first metallic structure 9102 is coupled to asecond metallic structure 9104. Preferably, the first metallic structure9102 and the second metallic structure 9104 are pre-existing componentsof the assembly. For example, the first metallic structure 9102 could bea first clamshell 9106 and the second metallic structure 9104 could be asecond clamshell. Alternatively, the first metallic structure 9102 couldbe a first metal geometry 9110, such as a metallic housing of asolenoid, and the second metallic structure 9104 could be a second metalgeometry 9112, such as a ground plane of a PCB circuit board. While itis preferable that the first metallic structure 9102 and the secondmetallic structure 9104 be pre-existing components of the assembly, insome specific embodiments, these structures could be added to theassembly solely for this use.

At least one impedance-matching structure 9116, such as an inductor orcapacitor, may be coupled with the first metallic structure 9102 and thesecond metallic structure 9104 to match the impedance of the apparatusto the interrogator frequency. In some embodiments, more than oneimpedance matching structure 9116 may be used in combination, such as acombination of an inductor and a capacitor (e.g., in either a parallelor series configuration, to form a tank circuit).

At least for the purpose of ground continuity, a low pass filter 9114 ispreferably coupled with the first metallic structure 9102 and the secondmetallic structure 9104. The low pass filter 9114 preferably has acutoff frequency sufficiently below the frequency (approximately 900MHz) of a commercially available RFID interrogator 9122.

The apparatus 9100 operates by performing at least two functions. In afirst function, the apparatus 9100 is impedance matched at theinterrogator frequency using the at least one impedance-matchingstructure 9116, limiting or essentially prohibiting reflection of theinterrogator frequency. In a second function, the metallic structures9102, 9104 are shorted together using a shorting mechanism 9118, such asa transistor or switch. The shorting can be controlled by amicroprocessor 9120. This shorting momentarily eliminates the impedancematching and causes a change in reflection. The transition from thefirst function to the second function causes a shift in the reflectioncoefficient of the coupled first metallic structure 9102 and secondmetallic structure 9104. By shorting the metallic structures 9102, 9104together as desired, data can be transmitted to a commercially availableRFID interrogator 9122, coded in the resulting reflection gamma.

In some embodiments, an obstruction (e.g., condensation or droplets dueto splashing) may render obtaining an accurate image of a drip chamberby an image sensor (e.g., the drip chamber 4 and the image sensor 11 ofFIG. 1) difficult. FIG. 92 is an image of such an obstructed dripchamber 9200. The drip chamber 9202 includes a fluid drop 9204 and anobstruction 9206. The obstruction 9206 may include fluid droplets fromcondensation or splashing in some embodiments. FIG. 93 shows a flowchart diagram of a method 9300 for obtaining an image of a drip chamberin accordance with an embodiment of the present disclosure. The method9300 includes acts 9302, 9304, 9306, and 9308. Method 9300 may beimplemented by the processor 15 of FIG. 1 and may be implemented as aprocessor-implemented method, as a set of instructions configured forexecution by one or more processors, in hardware, in software, the like,or some combination thereof.

Act 9302 of method 9300 includes capturing an image of a drip chamber.Act 9304 of method 9300 includes determining that the image of the dripchamber includes a visual obstruction. The visual obstruction may besimilar to the visual obstruction shown in FIG. 92 in some embodiments.Act 9306 of method 9300 includes applying a blurring function to thecaptured image of Act 9302 upon a determination that the captured imageof Act 9302 contains a visual obstruction. The blurring function may beany function that decreases the amount or eliminates an amount of detailin the captured image of Act 9302. In some embodiments, the blurringfunction may be applied without regard to a determination that thecaptured image of Act 9302 contains a visual obstruction, i.e., theblurring function is always applied to the captured image of Act 9302.

In some embodiments, the blurring function of Act 9306 may includeapplying a low-pass filter to the captured image of Act 9302. Thelow-pass filter or other blurring function may be applied in either ahorizontal direction (e.g., an X-direction in Cartesian coordinates) ofthe captured image of Act 9302, or a vertical direction (e.g., aY-direction in Cartesian coordinates) of the captured image of Act 9302.In some embodiments, the low pass filter or blurring function may beapplied in both a horizontal and vertical direction (e.g., in both an Xand Y direction in Cartesian coordinates) of the captured image of Act9302.

In some embodiments, the blurring function of Act 9306 may includeapplying a Gaussian Blur function to the captured image of Act 9302. Ifthe blurring function or the low pass filter is applied in either avertical or a horizontal direction, as described above, the low passfilter or blurring function may then include a one-dimensional GaussianBlur function in some embodiments. If the blurring function or the lowpass filter is applied in both a vertical and a horizontal direction, asdescribed above, the low pass filter or blurring function may theninclude a two-dimensional Gaussian Blur function in some embodiments.

After the blurring function is applied, enough detail should beeliminated from the captured image such that Act 9308 can be carriedout. Act 9308 includes determining if the captured image of Act 9302contains a match to a template. In some embodiments, a processor (e.g.,the processor 15 of FIG. 1) may use a template matching function todetermine if the captured image of Act 9302 contains a match to thetemplate. In some embodiments, the template matching function may be anOpenCV template matching function. The template may include at least apartial image of a fluid drop. In some embodiments, the template mayinclude at least a partial image of a fluid drop being backlit by alighting source. In yet a further embodiment, the lighting source mayinclude an LED array (e.g., the LED array 20 of FIG. 1).

FIG. 94 is a graphical representation 9400 of an embodiment featuring aplurality of drops successively growing within a drip chamber until eachfalls, as seen by an image sensor (e.g., the drip chamber 4 and imagesensor 11 of FIG. 1). The image sensor communicates an output signal toa processor (e.g., the processor 15 of FIG. 1), the processor configuredto determine from the output signal when a fluid drop has fallen withinthe drip chamber. The curve 9408 to the left of time marker 9406represents the image sensor's output signal prior to application of ablurring function (e.g., the blurring function of Act 9206 of FIG. 92).Similarly, the curve 9410 to the right of time marker 9406 representsthe image sensor's output signal after the application of the blurringfunction. According to the curve 9408 and the curve 9410 of FIG. 94,application of the blurring function may reduce the amount of noise inthe image sensor's output signal. This reduction of noise in the outputsignal allows the processor to more efficiently identify, from the imagesensor's output signal, when a drop of fluid has fallen inside the dripchamber.

In some embodiments, the processor is configured to recognize that adrop has fallen within the drip chamber, but only if certain currentevents and prior events have occurred, i.e. the processor performs ahysteresis function. In one embodiment, the processor will recognizethat a drop has fallen within the drip chamber when the curve crosses alower threshold limit 9404, but only if the curve has previously crossedan upper threshold limit 9402 since the previous crossing of the lowerthreshold limit 9404. This hysteresis function may be used to avoid theprocessor erroneously registering that a drop has fallen due to noise inthe image sensor's output signal.

Referring now to FIG. 95, in some embodiments, it may be desirable torely on some means other than or in addition to an audible noise orvisual indicator to convey the status of a device 9500. This may bedesirable where a device 9500 is used in an environment with high levelsof ambient noise and or high level of ambient light respectively. Thismay in some embodiments, be cheaply accomplished using a signatureanalyzer 9502.

During normal device 9500 function, EM emissions will be created. Theseemissions are a natural artifact of how digital functions are executedby the device 9500. Additionally, specific digital functions of thedevice 9500 will produce EM signatures in a predictable manner. That is,when a digital function is performed by the device 9500, an EM emissioncorresponding to that function may occur. In FIG. 95, the device 9500includes a component 9504 which may perform a digital function. Thiscomponent may, for example, be a microprocessor, clock, etc.

The EM signatures of specific functions may be empirically determined. Asignature analyzer 9502 may monitor the EM emissions of the device 9500.A received EM signature may be matched to its empirically determinedmeaning. In this manner, a signature analyzer 9502 may divine whatdigital functions are being performed by the device 9500 using the EMemissions from the device 9500.

In a specific example, the device 9500 may be a medication deliverydevice. A medication delivery device may generate an occlusion alarmduring operation. The generation of this occlusion alarm will cause aspecific EM signature to be emitted from the medication delivery device.A signature analyzer 9502 monitoring emissions from the medicationdelivery device may receive and analyze this specific emission signatureand thereby determine that the medication delivery device is issuing anocclusion alarm.

Various components which create EM emissions may be contained within anEM shield 9506. This shield 9506 may suppress emissions from the device9500 such that the device 9500 does not interfere with other devices(not shown) in the vicinity and conforms to any local requirements. Theshield 9506, however, will not totally eliminate emissions from thedevice 9500. Reduced amplitude frequency emissions 9508 which satisfyregulatory compliance levels will still occur. In one embodiment whichuses a signature analyzer 9502 to monitor the EM signature of a device9500, the signature analyzer 9502 may be suitably positioned outside ofthe shield 9506 and may monitor these reduced amplitude frequencyemissions 9508. In such embodiments, the signature analyzer 9502 may bean RF receiver such as a narrowband receiver. Such a receiver is capableof being tuned to very specific and reduced emission frequencies.Additionally, using a narrowband receiver may be desirable because sucha receiver is relatively cheap.

In some embodiments, a medical pump device may keep track of the numberof infusion sets that the medical pump device administers. The medicalpump device may keep track of the infusion sets by utilizing a softwareradio, operably connected to the medical pump device. The software radiomay include a coiled wire operably engaged with a microchip in themedical pump device, such that the microchip can transmit signals viathe coiled wire.

The software radio, in some embodiments, may be used to transmit acommunication signal to a handheld device that is configured to receivethe signal. The communication signal may be a number of infusion setsthat the medical pump device has administered.

Further, in some embodiments, the medical pump device may communicatewith the handheld device via a speaker on the handheld device configuredto receive an acoustic or audio signal from the medical pump device. Theaudio signal, in some embodiments, may include digital data that isencoded in the audio signal.

In some embodiments, the medical pump device may communicate with ahandheld device by utilizing a motion sensor in the handheld device. Themotion sensor may receive motion input from a motion generator includedin the medical pump device. The motion generator, in some embodiments,may be a stepper motor, and, further, in some embodiments, the motionsensor may be an accelerometer. The handheld device may be configured todetermine a number of infusion sets that the medical pump device hasadministered from the motion input received by the motion sensor.

The medical pump device may be configured to pair with a handheld devicein order to establish wireless communication with the handheld device.In some embodiments, the medical pump device may establish a Blue Toothconnection with the handheld device. In yet other embodiments, themedical pump device may establish a wireless communication signal withthe handheld device by utilizing near-field communication (NFC) signals.

In some embodiments, the medical pump device may communicate with ahandheld device by utilizing a camera that is included in the handhelddevice. More specifically, the camera of the handheld device may beconfigured to detect a visual modulation signal. In some embodiments,the visual modulation signal may come from a dome light included in themedical pump device. The handheld device may use the visual modulationsignal to determine a number of infusion sets that has been administeredby the medical pump device.

Various alternatives and modifications can be devised by those skilledin the art without departing from the disclosure. Accordingly, thepresent disclosure is intended to embrace all such alternatives,modifications and variances. Additionally, while several embodiments ofthe present disclosure have been shown in the drawings and/or discussedherein, it is not intended that the disclosure be limited thereto, as itis intended that the disclosure be as broad in scope as the art willallow and that the specification be read likewise. Therefore, the abovedescription should not be construed as limiting, but merely asexemplifications of particular embodiments. And, those skilled in theart will envision other modifications within the scope and spirit of theclaims appended hereto. Other elements, steps, methods and techniquesthat are insubstantially different from those described above and/or inthe appended claims are also intended to be within the scope of thedisclosure.

The embodiments shown in the drawings are presented only to demonstratecertain examples of the disclosure. And, the drawings described are onlyillustrative and are non-limiting. In the drawings, for illustrativepurposes, the size of some of the elements may be exaggerated and notdrawn to a particular scale. Additionally, elements shown within thedrawings that have the same numbers may be identical elements or may besimilar elements, depending on the context.

Where the term “comprising” is used in the present description andclaims, it does not exclude other elements or steps. Where an indefiniteor definite article is used when referring to a singular noun, e.g.,“a,” “an,” or “the,” this includes a plural of that noun unlesssomething otherwise is specifically stated. Hence, the term “comprising”should not be interpreted as being restricted to the items listedthereafter; it does not exclude other elements or steps, and so thescope of the expression “a device comprising items A and B” should notbe limited to devices consisting only of components A and B. Thisexpression signifies that, with respect to the present disclosure, theonly relevant components of the device are A and B.

Furthermore, the terms “first,” “second,” “third,” and the like, whetherused in the description or in the claims, are provided fordistinguishing between similar elements and not necessarily fordescribing a sequential or chronological order. It is to be understoodthat the terms so used are interchangeable under appropriatecircumstances (unless clearly disclosed otherwise) and that theembodiments of the disclosure described herein are capable of operationin other sequences and/or arrangements than are described or illustratedherein.

The invention claimed is:
 1. A flow meter, comprising: a coupler adapted to couple to a drip chamber; a support member operatively coupled to the coupler; an image sensor having a field of view and operatively coupled to the support member, wherein the image sensor is positioned to view the drip chamber within the field of view; and at least one processor operatively coupled to the image sensor to receive image data therefrom, wherein the at least one processor is configured to: capture an image including an image of the drip chamber using the image sensor having the field of view including the drip chamber; subtract the image from a dynamic background image to thereby generate a difference image; and examine the difference image to determine whether a free flow condition exists.
 2. The flow meter according to claim 1, wherein the at least one processor is further configured to calculate a plurality of summation values.
 3. The flow meter according to claim 1, wherein the at least one processor is configured to examine the difference image to determine whether the free flow condition exists by: converting each pixel of the difference image to a true value if an absolute value of a respective pixel is beyond a predetermined threshold or to a false value if the absolute value of the respective pixel is less than the predetermined threshold; and summing each row of the converted difference image to generate a plurality of summation values, wherein each summation value of the plurality of summation values corresponds to a respective row of the converted difference image.
 4. The flow meter according to claim 3, wherein the at least one processor is further configured to determine if the free flow condition exists within the drip chamber by examining the plurality of summation values.
 5. The flow meter according to claim 4, wherein the at least one processor is further configured to determine if the plurality of summation values includes a plurality of contiguous summation values above another predetermined threshold when the at least one processor determines if the free flow condition exists.
 6. The flow meter according to claim 4, wherein the at least one processor is further configured to determine if a drop has been formed within the drip chamber when the at least one processor examines the plurality of summation values.
 7. The flow meter according to claim 6, wherein the at least one processor is further configured to determine that the drop has been formed if the plurality of summation values includes a plurality of contiguous summation values within a predetermined range greater than a minimum value and less than a maximum value and a location of the plurality of contiguous summation values corresponds to a predetermined range of locations in which the drop can form.
 8. The flow meter according to claim 4, the at least one processor is further configured to smooth the plurality of summation values prior to when the at least one processor examines the plurality of summation values.
 9. The flow meter according to claim 8, wherein the at least one processor smoothes in accordance with at least one of a spline function, a cubic spline function, a B-spline function, a Bezier spline function, a polynomial interpolation, a moving average, a data smoothing function, and a cubic-spline-type function.
 10. The flow meter according to claim 1, wherein the at least one processor is further configured to initialize the dynamic background image.
 11. The flow meter according to claim 1, wherein the at least one processor is further configured to update the dynamic background image using the image captured by the image sensor.
 12. The flow meter according to claim 11, wherein the dynamic background image is updated in accordance with: P _(background,i,j) =P _(background,i,j)(1−α_(background))+α_(background) P _(input,i,j).
 13. The flow meter as in claim 11, wherein the at least one processor is further configured to update an array of variances using the image captured by the image sensor.
 14. The flow meter according to claim 13, wherein the array of variances is updated in accordance with: σ_(temp) ²=(P _(background,i,j) −P _(input,i,j))² σ_(background,i,j)=σ_(background,i,j) ²(1−β_(background))+β_(background)σ_(temp) ².
 15. The flow meter according to claim 11, wherein the at least one processor is further configured to update an array of integers in according with the image captured by the image sensor.
 16. The flow meter according to claim 15, wherein each integer of the array of integers corresponds to a number of updates of a pixel of the dynamic background image.
 17. The flow meter according to claim 16, wherein a comparison of the image to the dynamic background image only compares pixels within the image to pixels within the dynamic background image if a respective integer of the array of integers indicates a respective pixel within the dynamic background image has been updated at least a predetermined number of times.
 18. A processor-implemented method implemented by an operative set of processor executable instruction configured for execution on at least one processor, the method comprising: capturing an image of a drip chamber and a background pattern disposed behind the drip chamber, wherein the image is captured using an image sensor; subtracting the image from a dynamic background image to thereby generate a difference image; and examining the difference image to determine whether a free flow condition exists based upon a distortion of the background pattern as indicated by the captured image.
 19. The method according to claim 18, further comprising initializing the dynamic background image.
 20. The method according to claim 18, further comprising updating the dynamic background image using the image captured by the image sensor.
 21. The method according to claim 20, wherein the dynamic background image is updated in accordance with: P _(background,i,j) =P _(background,i,j)(1−α_(background))+α_(background) P _(input,i,j).
 22. The method according to claim 20, further comprising updating an array of variances using the image captured by the image sensor.
 23. The method according to claim 22, wherein the array of variances is updated in accordance with: σ_(temp) ²=(P _(background,i,j) −P _(input,i,j))² σ_(background,i,j)=σ_(background,i,j) ²(1−β_(background))+β_(background)σ_(temp) ².
 24. The method according to claim 20, further comprising updating an array of integers in accordance with the image captured by the image sensor.
 25. The method according to claim 24, wherein each integer of the array of integers corresponds to a number of updates of a pixel of the dynamic background image.
 26. The method according to 25, wherein a comparison of the image to the dynamic background image only compares pixels within the image to pixels within the dynamic background image if a respective integer of the array of integers indicates a respective pixel within the dynamic background image has been updated at least a predetermined number of times.
 27. The method according to claim 18, further comprising identifying a drop in the image and a predetermined band near an edge of the drop; and initializing the dynamic background image by setting each pixel of the dynamic background image to the image unless it is within the identified drop or the predetermined band near the edge of the drop.
 28. The method according to claim 27, further comprising setting a pixel of the dynamic background image to a predetermined value if a corresponding pixel of the image is within the identified drop or the predetermined band near the edge of the drop.
 29. The method according to claim 28, wherein the corresponding pixel of the image has a location corresponding to a location of the pixel of the dynamic background image.
 30. The method according to claim 29, further comprising determining a baseline corresponding to an opening of the drip chamber.
 31. The method according to claim 30, wherein an act of determining a subset of pixels within a plurality of pixels of interest that corresponds to the drop includes determining each of the plurality of pixels of interest is within the subset of pixels if the respective pixel of the plurality of pixels of interest has a contiguous path back to the baseline of the drop forming at an opening of the drip chamber.
 32. The method according to claim 18, further comprising: capturing a first image using the image sensor; identifying a drop within the first image and a predetermined band near an edge of the drop; initializing the dynamic background image by setting each pixel to the first image unless it is within the identified drop or the predetermined band near the edge of the drop; setting pixels within a region of the drop or within the predetermined band to a predetermined value; initializing an array of integers; and initializing an array of variances.
 33. The method according to claim 32, further comprising updating the dynamic background image, the array of integers, and the array of variances using the image. 